diff --git a/src/proto_alpha/lib_benchmarks_proto/dal_benchmarks.ml b/src/proto_alpha/lib_benchmarks_proto/dal_benchmarks.ml
index 82a1f5aa6a992804af612ed4f14521cc1e3a3b68..8e2f3b535e2f81605fe41e5c79dbb5876338d160 100644
--- a/src/proto_alpha/lib_benchmarks_proto/dal_benchmarks.ml
+++ b/src/proto_alpha/lib_benchmarks_proto/dal_benchmarks.ml
@@ -107,7 +107,12 @@ module Publish_commitment : Benchmark.S = struct
       in
       let workload = () in
       let closure () =
-        match Dal_apply.apply_publish_commitment ctxt op with
+        match
+          Dal_apply.apply_publish_commitment
+            ctxt
+            op
+            ~source:Environment.Signature.Public_key_hash.zero
+        with
         | Error errs ->
             Format.eprintf "%a@." Environment.Error_monad.pp_trace errs ;
             Stdlib.failwith
diff --git a/src/proto_alpha/lib_dal/dal_plugin_registration.ml b/src/proto_alpha/lib_dal/dal_plugin_registration.ml
index 7c8e5bf51a6efd583961c817f3791e473c68c4a9..d80fffd99475fea2e2e7de35db097dcb97964c7f 100644
--- a/src/proto_alpha/lib_dal/dal_plugin_registration.ml
+++ b/src/proto_alpha/lib_dal/dal_plugin_registration.ml
@@ -275,7 +275,9 @@ module Plugin = struct
 
                Not resilient to DAL parameters change. *)
             ~number_of_slots:dal_constants.number_of_slots
-            attested_slot_headers
+            (List.map
+               (fun ext -> ext.Dal.Slot.Header.header)
+               attested_slot_headers)
           |> Environment.wrap_tzresult
         in
         (* 7. We finally export and return the cells alongside their hashes as a
diff --git a/src/proto_alpha/lib_plugin/RPC.ml b/src/proto_alpha/lib_plugin/RPC.ml
index e8c0d72df73ac222e400a434d2c3cb66b7e93a15..793e0d1d26834e7f9bcccbe0da1f1f40e16f37e1 100644
--- a/src/proto_alpha/lib_plugin/RPC.ml
+++ b/src/proto_alpha/lib_plugin/RPC.ml
@@ -3210,7 +3210,7 @@ module Dal = struct
         RPC_path.(path / "shards")
 
     let published_slot_headers =
-      let output = Data_encoding.(list Dal.Slot.Header.encoding) in
+      let output = Data_encoding.(list Dal.Slot.Header.extended_encoding) in
       RPC_service.get_service
         ~description:"Get the published slots headers for the given level"
         ~query:level_query
diff --git a/src/proto_alpha/lib_protocol/alpha_context.mli b/src/proto_alpha/lib_protocol/alpha_context.mli
index 7b68e75c6818e8a58fce1765c34d8a7b5c3f8c10..6f2a371cc7df0e31ba37394dc80bae5b59292008 100644
--- a/src/proto_alpha/lib_protocol/alpha_context.mli
+++ b/src/proto_alpha/lib_protocol/alpha_context.mli
@@ -2859,10 +2859,14 @@ module Dal : sig
 
       type t = {id : id; commitment : Commitment.t}
 
+      type extended = {header : t; source : Signature.public_key_hash}
+
       val id_encoding : id Data_encoding.t
 
       val encoding : t Data_encoding.t
 
+      val extended_encoding : extended Data_encoding.t
+
       val pp_id : Format.formatter -> id -> unit
 
       val pp : Format.formatter -> t -> unit
@@ -2870,20 +2874,22 @@ module Dal : sig
       val equal : t -> t -> bool
     end
 
-    val register_slot_header : context -> Header.t -> context tzresult
+    val register_slot_header : context -> Header.extended -> context tzresult
 
     val find_slot_headers :
-      context -> Raw_level.t -> Header.t list option tzresult Lwt.t
+      context -> Raw_level.t -> Header.extended list option tzresult Lwt.t
 
     val finalize_current_slot_headers : context -> context Lwt.t
 
     val finalize_pending_slot_headers :
-      context -> number_of_slots:int -> (context * Attestation.t) tzresult Lwt.t
+      context ->
+      number_of_slots:int ->
+      (context * Attestation.t * Header.extended list) tzresult Lwt.t
 
     val compute_attested_slot_headers :
       is_slot_attested:(Header.t -> bool) ->
-      Header.t list ->
-      Header.t list * Attestation.t
+      Header.extended list ->
+      Header.extended list * Attestation.t
   end
 
   module Operations : sig
diff --git a/src/proto_alpha/lib_protocol/apply.ml b/src/proto_alpha/lib_protocol/apply.ml
index add25bdc4430910f7a3f692a237f5ddeae7dab41..f6ca4b4cd882b56a55144d65171ee4c9ad0a7be0 100644
--- a/src/proto_alpha/lib_protocol/apply.ml
+++ b/src/proto_alpha/lib_protocol/apply.ml
@@ -1461,7 +1461,7 @@ let apply_manager_operation :
             [] )
     | Dal_publish_commitment slot_header ->
         let*? ctxt, slot_header =
-          Dal_apply.apply_publish_commitment ctxt slot_header
+          Dal_apply.apply_publish_commitment ctxt slot_header ~source
         in
         let consumed_gas = Gas.consumed ~since:ctxt_before_op ~until:ctxt in
         let result =
@@ -3049,7 +3049,10 @@ let finalize_application ctxt block_data_contents ~round ~predecessor_hash
     may_start_new_cycle ctxt
   in
   let* ctxt = Amendment.may_start_new_voting_period ctxt in
-  let* ctxt, dal_attestation = Dal_apply.finalisation ctxt in
+  (* TODO: push _attested_slot_headers into rollups' inbox *)
+  let* ctxt, dal_attestation, _attested_slot_headers =
+    Dal_apply.finalisation ctxt
+  in
   let* ctxt = Sc_rollup.Inbox.finalize_inbox_level ctxt in
   let balance_updates =
     migration_balance_updates @ baking_receipts @ cycle_end_balance_updates
diff --git a/src/proto_alpha/lib_protocol/dal_apply.ml b/src/proto_alpha/lib_protocol/dal_apply.ml
index c3c5b1aa16fc7e41175c7ae1d0c78142caf6a3e4..43657f0a503b5aa0c1cf6952b3b7b07b1d70c6a9 100644
--- a/src/proto_alpha/lib_protocol/dal_apply.ml
+++ b/src/proto_alpha/lib_protocol/dal_apply.ml
@@ -87,7 +87,7 @@ let apply_attestation ctxt attestation ~power =
 let validate_publish_commitment ctxt _operation =
   assert_dal_feature_enabled ctxt
 
-let apply_publish_commitment ctxt operation =
+let apply_publish_commitment ctxt operation ~source =
   let open Result_syntax in
   let* ctxt = Gas.consume ctxt Dal_costs.cost_Dal_publish_commitment in
   let number_of_slots = Dal.number_of_slots ctxt in
@@ -100,14 +100,15 @@ let apply_publish_commitment ctxt operation =
       ~current_level
       operation
   in
-  let* ctxt = Dal.Slot.register_slot_header ctxt slot_header in
+  let extended_header = Dal.Slot.Header.{header = slot_header; source} in
+  let* ctxt = Dal.Slot.register_slot_header ctxt extended_header in
   return (ctxt, slot_header)
 
 let finalisation ctxt =
   let open Lwt_result_syntax in
   only_if_dal_feature_enabled
     ctxt
-    ~default:(fun ctxt -> return (ctxt, Dal.Attestation.empty))
+    ~default:(fun ctxt -> return (ctxt, Dal.Attestation.empty, []))
     (fun ctxt ->
       let*! ctxt = Dal.Slot.finalize_current_slot_headers ctxt in
       (* The fact that slots confirmation is done at finalization is very
@@ -126,7 +127,7 @@ let finalisation ctxt =
            level where the game started.
       *)
       let number_of_slots = (Constants.parametric ctxt).dal.number_of_slots in
-      let+ ctxt, attestation =
+      let+ ctxt, attestation, attested_slot_headers =
         Dal.Slot.finalize_pending_slot_headers ctxt ~number_of_slots
       in
-      (ctxt, attestation))
+      (ctxt, attestation, attested_slot_headers))
diff --git a/src/proto_alpha/lib_protocol/dal_apply.mli b/src/proto_alpha/lib_protocol/dal_apply.mli
index 55bd78051f1a89805bdb6188d641cdd75e68b9a1..98fe9e40a8b1fea7b87c66ef17ca2ffd69bd435b 100644
--- a/src/proto_alpha/lib_protocol/dal_apply.mli
+++ b/src/proto_alpha/lib_protocol/dal_apply.mli
@@ -57,11 +57,14 @@ val apply_attestation : t -> Dal.Attestation.t -> power:int -> t tzresult
 val validate_publish_commitment :
   t -> Dal.Operations.Publish_commitment.t -> unit tzresult
 
-(** [apply_publish_commitment ctxt slot_header] applies the publication of
-   slot header [slot_header] on top of [ctxt]. Fails if the slot contains
-   already a slot header. *)
+(** [apply_publish_commitment ctxt slot_header ~source] applies the publication
+    of slot header [slot_header] on top of [ctxt]. Fails if the slot contains
+    already a slot header. *)
 val apply_publish_commitment :
-  t -> Dal.Operations.Publish_commitment.t -> (t * Dal.Slot.Header.t) tzresult
+  t ->
+  Dal.Operations.Publish_commitment.t ->
+  source:public_key_hash ->
+  (t * Dal.Slot.Header.t) tzresult
 
 (** [finalisation ctxt] should be executed at block finalisation
    time. A set of slots attested at level [ctxt.current_level - lag]
@@ -69,4 +72,5 @@ val apply_publish_commitment :
 
    [lag] is a parametric constant specific to the data-availability
    layer.  *)
-val finalisation : t -> (t * Dal.Attestation.t) tzresult Lwt.t
+val finalisation :
+  t -> (t * Dal.Attestation.t * Dal.Slot.Header.extended list) tzresult Lwt.t
diff --git a/src/proto_alpha/lib_protocol/dal_slot_repr.ml b/src/proto_alpha/lib_protocol/dal_slot_repr.ml
index c1d216aee8850cbeace00167e4d7ac2354be263d..5021943b41a97d980793ecb4b29310371dbf0416 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_repr.ml
+++ b/src/proto_alpha/lib_protocol/dal_slot_repr.ml
@@ -63,6 +63,8 @@ module Header = struct
 
   type t = {id : id; commitment : Commitment.t}
 
+  type extended = {header : t; source : Signature.public_key_hash}
+
   let slot_id_equal {published_level; index} s2 =
     Raw_level_repr.equal published_level s2.published_level
     && Dal_slot_index_repr.equal index s2.index
@@ -100,6 +102,15 @@ module Header = struct
              (fun ((), x) -> x);
          ])
 
+  let extended_encoding =
+    let open Data_encoding in
+    conv
+      (fun {header; source} -> (header, source))
+      (fun (header, source) -> {header; source})
+      (obj2
+         (req "header" encoding)
+         (req "source" Signature.Public_key_hash.encoding))
+
   let pp_id fmt {published_level; index} =
     Format.fprintf
       fmt
@@ -218,7 +229,7 @@ module Slot_market = struct
 
   module Slot_index_map = Map.Make (Dal_slot_index_repr)
 
-  type t = {length : int; slot_headers : Header.t Slot_index_map.t}
+  type t = {length : int; slot_headers : Header.extended Slot_index_map.t}
 
   let init ~length =
     if Compare.Int.(length < 0) then
@@ -228,8 +239,9 @@ module Slot_market = struct
 
   let length {length; _} = length
 
-  let register t new_slot_header =
+  let register t new_extended_slot_header =
     let open Header in
+    let new_slot_header = new_extended_slot_header.header in
     if
       not
         Compare.Int.(
@@ -241,7 +253,7 @@ module Slot_market = struct
       let update = function
         | None ->
             has_changed := true ;
-            Some new_slot_header
+            Some new_extended_slot_header
         | Some x -> Some x
       in
       let slot_headers =
diff --git a/src/proto_alpha/lib_protocol/dal_slot_repr.mli b/src/proto_alpha/lib_protocol/dal_slot_repr.mli
index 40c8f94c91f02258ff1d024983f0553e21f924ca..80cd7526675324a142e2539d1b578715869cb493 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_repr.mli
+++ b/src/proto_alpha/lib_protocol/dal_slot_repr.mli
@@ -93,12 +93,17 @@ module Header : sig
      slot's commitment. *)
   type t = {id : id; commitment : Commitment.t}
 
+  type extended = {header : t; source : Signature.public_key_hash}
+
   (** encoding for values of type {!type-id}. *)
   val id_encoding : id Data_encoding.t
 
   (** encoding for values of type {!t}. *)
   val encoding : t Data_encoding.t
 
+  (** encoding for values of type {!extended}. *)
+  val extended_encoding : extended Data_encoding.t
+
   (** pretty-printer for values of type {!type-id}. *)
   val pp_id : Format.formatter -> id -> unit
 
@@ -192,10 +197,10 @@ module Slot_market : sig
      registered. Returns [Some (_, false)] otherwise. Returns [None]
      if the [index] is not in the interval [0;length] where [length]
      is the value provided to the [init] function. *)
-  val register : t -> Header.t -> (t * bool) option
+  val register : t -> Header.extended -> (t * bool) option
 
   (** [candidates t] returns a list of slot header candidates. *)
-  val candidates : t -> Header.t list
+  val candidates : t -> Header.extended list
 end
 
 (** This module provides an abstract data structure (type {!History.t}) that
diff --git a/src/proto_alpha/lib_protocol/dal_slot_storage.ml b/src/proto_alpha/lib_protocol/dal_slot_storage.ml
index 944056b4f2b322c01835e09760c39f55bce109ae..88d985713133a05dce8cf5352cb7fccf579331ff 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_storage.ml
+++ b/src/proto_alpha/lib_protocol/dal_slot_storage.ml
@@ -33,9 +33,11 @@ let finalize_current_slot_headers ctxt =
 
 let compute_attested_slot_headers ~is_slot_attested seen_slot_headers =
   let open Dal_slot_repr in
-  let fold_attested_slots (rev_attested_slot_headers, attestation) slot =
+  let fold_attested_slots (rev_attested_slot_headers, attestation) extended_slot
+      =
+    let slot = extended_slot.Header.header in
     if is_slot_attested slot then
-      ( slot :: rev_attested_slot_headers,
+      ( extended_slot :: rev_attested_slot_headers,
         Dal_attestation_repr.commit attestation slot.Header.id.index )
     else (rev_attested_slot_headers, attestation)
   in
@@ -58,6 +60,9 @@ let update_skip_list ctxt ~confirmed_slot_headers ~level_attested
     ~number_of_slots =
   let open Lwt_result_syntax in
   let* slots_history = get_slot_headers_history ctxt in
+  let confirmed_slot_headers =
+    List.map (fun ext -> ext.Dal_slot_repr.Header.header) confirmed_slot_headers
+  in
   let*? slots_history =
     Dal_slot_repr.History.add_confirmed_slot_headers_no_cache
       ~number_of_slots
@@ -73,11 +78,11 @@ let finalize_pending_slot_headers ctxt ~number_of_slots =
   let {Level_repr.level = raw_level; _} = Raw_context.current_level ctxt in
   let Constants_parametric_repr.{dal; _} = Raw_context.constants ctxt in
   match Raw_level_repr.(sub raw_level dal.attestation_lag) with
-  | None -> return (ctxt, Dal_attestation_repr.empty)
+  | None -> return (ctxt, Dal_attestation_repr.empty, [])
   | Some level_attested ->
       let* seen_slots = find_slot_headers ctxt level_attested in
       let*! ctxt = Storage.Dal.Slot.Headers.remove ctxt level_attested in
-      let* ctxt, attestation, confirmed_slot_headers =
+      let* ctxt, attestation, attested_slot_headers =
         match seen_slots with
         | None -> return (ctxt, Dal_attestation_repr.empty, [])
         | Some seen_slots ->
@@ -94,8 +99,8 @@ let finalize_pending_slot_headers ctxt ~number_of_slots =
       let* ctxt =
         update_skip_list
           ctxt
-          ~confirmed_slot_headers
+          ~confirmed_slot_headers:attested_slot_headers
           ~level_attested
           ~number_of_slots
       in
-      return (ctxt, attestation)
+      return (ctxt, attestation, attested_slot_headers)
diff --git a/src/proto_alpha/lib_protocol/dal_slot_storage.mli b/src/proto_alpha/lib_protocol/dal_slot_storage.mli
index 4dc2d270fca377d7bb566d726e436d56f39636cb..d1e9bf29a36cfc02d5359a17ea1a0a3d27361a64 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_storage.mli
+++ b/src/proto_alpha/lib_protocol/dal_slot_storage.mli
@@ -51,7 +51,7 @@
 val find_slot_headers :
   Raw_context.t ->
   Raw_level_repr.t ->
-  Dal_slot_repr.Header.t list option tzresult Lwt.t
+  Dal_slot_repr.Header.extended list option tzresult Lwt.t
 
 (** [finalize_current_slot_headers ctxt] finalizes the current slot
    headers posted on this block and marks them as pending into the
@@ -66,7 +66,9 @@ val finalize_current_slot_headers : Raw_context.t -> Raw_context.t Lwt.t
 val finalize_pending_slot_headers :
   Raw_context.t ->
   number_of_slots:int ->
-  (Raw_context.t * Dal_attestation_repr.t) tzresult Lwt.t
+  (Raw_context.t * Dal_attestation_repr.t * Dal_slot_repr.Header.extended list)
+  tzresult
+  Lwt.t
 
 (** [get_slot_headers_history ctxt] returns the current value of slots_history stored
    in [ctxt], or Slots_history.genesis if no value is stored yet. *)
@@ -78,5 +80,5 @@ val get_slot_headers_history :
     slot headers and the corresponding bitset. *)
 val compute_attested_slot_headers :
   is_slot_attested:(Dal_slot_repr.Header.t -> bool) ->
-  Dal_slot_repr.Header.t list ->
-  Dal_slot_repr.Header.t list * Dal_attestation_repr.t
+  Dal_slot_repr.Header.extended list ->
+  Dal_slot_repr.Header.extended list * Dal_attestation_repr.t
diff --git a/src/proto_alpha/lib_protocol/init_storage.ml b/src/proto_alpha/lib_protocol/init_storage.ml
index eff9f1abc5387dd5ca85f620aa29cf0865283d15..b31801241409ecdba8dad1c2384fda38916134a9 100644
--- a/src/proto_alpha/lib_protocol/init_storage.ml
+++ b/src/proto_alpha/lib_protocol/init_storage.ml
@@ -207,6 +207,8 @@ let prepare_first_block chain_id ctxt ~typecheck_smart_contract
            that are not slashed whereas unstake_requests are slashed. *)
         let*! ctxt = Pending_denunciations_storage.clear ctxt in
         let*! ctxt = Raw_context.remove ctxt ["last_snapshot"] in
+        (* FIXME/DAL: reset "slot_headers" when migrating from P to Q, as the
+           type changed. *)
         return (ctxt, [])
   in
   let* ctxt =
diff --git a/src/proto_alpha/lib_protocol/raw_context.ml b/src/proto_alpha/lib_protocol/raw_context.ml
index b4d6028256ba28cf9c633a07790405c988167081..87af8e549c973a33d3efd5bef63dd87cedd4e9be 100644
--- a/src/proto_alpha/lib_protocol/raw_context.ml
+++ b/src/proto_alpha/lib_protocol/raw_context.ml
@@ -1782,12 +1782,13 @@ module Dal = struct
     in
     {ctxt with back = {ctxt.back with dal_attestation_slot_accountability}}
 
-  let register_slot_header ctxt slot_header =
+  let register_slot_header ctxt extended_slot_header =
     let open Result_syntax in
+    let slot_header = extended_slot_header.Dal_slot_repr.Header.header in
     match
       Dal_slot_repr.Slot_market.register
         ctxt.back.dal_slot_fee_market
-        slot_header
+        extended_slot_header
     with
     | None ->
         let length =
diff --git a/src/proto_alpha/lib_protocol/raw_context.mli b/src/proto_alpha/lib_protocol/raw_context.mli
index 1f34b498ba21119992bbcf0908fae58712ee4f41..5b8187c43f0cfea630206d0d8f0a67c556332329 100644
--- a/src/proto_alpha/lib_protocol/raw_context.mli
+++ b/src/proto_alpha/lib_protocol/raw_context.mli
@@ -444,11 +444,11 @@ module Dal : sig
      the candidate is registered. [Some (ctxt,false)] if another
      candidate was already registered previously. Returns an error if
      the slot is invalid. *)
-  val register_slot_header : t -> Dal_slot_repr.Header.t -> t tzresult
+  val register_slot_header : t -> Dal_slot_repr.Header.extended -> t tzresult
 
   (** [candidates ctxt] returns the current list of slot for which
      there is at least one candidate. *)
-  val candidates : t -> Dal_slot_repr.Header.t list
+  val candidates : t -> Dal_slot_repr.Header.extended list
 
   (** [is_slot_index_attested ctxt slot_index] returns [true] if the
      [slot_index] is declared available by the protocol. [false]
diff --git a/src/proto_alpha/lib_protocol/storage.ml b/src/proto_alpha/lib_protocol/storage.ml
index b1d0075db47f01a6142dd1304ad003bf4ee47335..354dc8560b82cd66e148ba84697b3f6439ce9549 100644
--- a/src/proto_alpha/lib_protocol/storage.ml
+++ b/src/proto_alpha/lib_protocol/storage.ml
@@ -2165,9 +2165,10 @@ module Dal = struct
           let name = ["slot_headers"]
         end)
         (struct
-          type t = Dal_slot_repr.Header.t list
+          type t = Dal_slot_repr.Header.extended list
 
-          let encoding = Data_encoding.(list Dal_slot_repr.Header.encoding)
+          let encoding =
+            Data_encoding.(list Dal_slot_repr.Header.extended_encoding)
         end)
 
     module History =
diff --git a/src/proto_alpha/lib_protocol/storage.mli b/src/proto_alpha/lib_protocol/storage.mli
index 12fbd3bccadd17fc6e8fbd793389ab364828f72a..e395dac7b827e7f4975a62ffbae4b7f3212aaf66 100644
--- a/src/proto_alpha/lib_protocol/storage.mli
+++ b/src/proto_alpha/lib_protocol/storage.mli
@@ -1010,7 +1010,7 @@ module Dal : sig
       Non_iterable_indexed_data_storage
         with type t = Raw_context.t
          and type key = Raw_level_repr.t
-         and type value = Dal_slot_repr.Header.t list
+         and type value = Dal_slot_repr.Header.extended list
 
     (** This is a permanent storage for slot headers confirmed by the L1. *)
     module History :