diff --git a/app/pdb/plug-in-cmds.c b/app/pdb/plug-in-cmds.c
index 1ff9320858..cd3696341d 100644
--- a/app/pdb/plug-in-cmds.c
+++ b/app/pdb/plug-in-cmds.c
@@ -314,7 +314,8 @@ register_plug_in_procs (GimpPDB *pdb)
                                "gimp-plug-in-domain-register");
   gimp_procedure_set_static_help (procedure,
                                   "Registers a textdomain for localisation.",
-                                  "This procedure adds a textdomain to the list of domains Gimp searches for strings when translating its menu entries. There is no need to call this function for plug-ins that have their strings included in the 'gimp-std-plugins' domain as that is used by default. If the compiled message catalog is not in the standard location, you may specify an absolute path to another location. This procedure can only be called in the query function of a plug-in and it has to be called before any procedure is installed.",
+                                  "This procedure adds a textdomain to the list of domains GIMP searches for strings when translating its menu entries.\n"
+                                     "Only core plug-ins should call this function directly. Third-party plug-ins are expected instead to define a custom `set_i18n()` method returning their domain and a path relative to their folder. In other words, this should be considered an internal PDB function which should not be used except by core developers.",
                                   NULL);
   gimp_procedure_set_static_attribution (procedure,
                                          "Sven Neumann <sven@gimp.org>",
diff --git a/libgimp/gimpplugin_pdb.c b/libgimp/gimpplugin_pdb.c
index 78ae928227..9e98bdc55d 100644
--- a/libgimp/gimpplugin_pdb.c
+++ b/libgimp/gimpplugin_pdb.c
@@ -34,14 +34,13 @@
  *
  * Registers a textdomain for localisation.
  *
- * This procedure adds a textdomain to the list of domains Gimp
- * searches for strings when translating its menu entries. There is no
- * need to call this function for plug-ins that have their strings
- * included in the 'gimp-std-plugins' domain as that is used by
- * default. If the compiled message catalog is not in the standard
- * location, you may specify an absolute path to another location. This
- * procedure can only be called in the query function of a plug-in and
- * it has to be called before any procedure is installed.
+ * This procedure adds a textdomain to the list of domains GIMP
+ * searches for strings when translating its menu entries.
+ * Only core plug-ins should call this function directly. Third-party
+ * plug-ins are expected instead to define a custom `set_i18n()` method
+ * returning their domain and a path relative to their folder. In other
+ * words, this should be considered an internal PDB function which
+ * should not be used except by core developers.
  *
  * Returns: TRUE on success.
  **/
diff --git a/pdb/groups/plug_in.pdb b/pdb/groups/plug_in.pdb
index de012e81d0..23fb0ad40c 100644
--- a/pdb/groups/plug_in.pdb
+++ b/pdb/groups/plug_in.pdb
@@ -61,14 +61,14 @@ sub plug_in_domain_register {
     $blurb = 'Registers a textdomain for localisation.';
 
     $help = <<'HELP';
-This procedure adds a textdomain to the list of domains Gimp searches 
-for strings when translating its menu entries. There is no need to 
-call this function for plug-ins that have their strings included in 
-the 'gimp-std-plugins' domain as that is used by default. If the compiled 
-message catalog is not in the standard location, you may specify an 
-absolute path to another location. This procedure can only be called 
-in the query function of a plug-in and it has to be called before any
-procedure is installed.
+This procedure adds a textdomain to the list of domains GIMP searches
+for strings when translating its menu entries.
+
+Only core plug-ins should call this function directly. Third-party
+plug-ins are expected instead to define a custom `set_i18n()` method
+returning their domain and a path relative to their folder. In other
+words, this should be considered an internal PDB function which should
+not be used except by core developers.
 HELP
 
     &neo_pdb_misc('2000');