Actually, don't send _misskey_quote anymore

lib/pleroma/web/activity_pub/transmogrifier.ex

@@ -668,13 +668,12 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
 
   def set_reply_to_uri(obj), do: obj
 
+  @doc """
+  Fedibird compatibility
+  https://github.com/fedibird/mastodon/commit/dbd7ae6cf58a92ec67c512296b4daaea0d01e6ac
+  """
   def set_quote_url(%{"quoteUrl" => quote_url} = object) when is_binary(quote_url) do
-    Map.merge(object, %{
-      # Fedibird quote
-      "quoteUri" => quote_url,
-      # Misskey quote
-      "_misskey_quote" => quote_url
-    })
+    Map.put(object, "quoteUri", quote_url)
   end
 
   def set_quote_url(obj), do: obj

priv/static/schemas/litepub-0.1.jsonld

@@ -17,7 +17,6 @@
             "ostatus": "http://ostatus.org#",
             "schema": "http://schema.org#",
             "toot": "http://joinmastodon.org/ns#",
-            "misskey": "https://misskey-hub.net/ns#",
             "fedibird": "http://fedibird.com/ns#",
             "value": "schema:value",
             "sensitive": "as:sensitive",
@@ -30,7 +29,6 @@
             },
             "quoteUrl": "as:quoteUrl",
             "quoteUri": "fedibird:quoteUri",
-            "_misskey_quote": "misskey:_misskey_quote",
             "oauthRegistrationEndpoint": {
                 "@id": "litepub:oauthRegistrationEndpoint",
                 "@type": "@id"

test/pleroma/web/activity_pub/transmogrifier_test.exs

@@ -385,7 +385,6 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
 
       assert modified["object"]["quoteUrl"] == quote_id
       assert modified["object"]["quoteUri"] == quote_id
-      assert modified["object"]["_misskey_quote"] == quote_id
     end
   end