diff -r 3bd08d0432d7 -r 39db5e268aaf src/Pure/PIDE/headless.scala
--- a/src/Pure/PIDE/headless.scala	Sun Jan 01 22:01:53 2023 +0100
+++ b/src/Pure/PIDE/headless.scala	Sun Jan 01 22:54:40 2023 +0100
@@ -306,7 +306,7 @@
       val dep_theories_set = dep_theories.toSet
       val dep_files =
         for (path <- dependencies.loaded_files)
-          yield Document.Node.Name(resources.append("", path))
+          yield Document.Node.Name(resources.append_path("", path))
 
       val use_theories_state = {
         val dep_graph = dependencies.theory_graph