diff -up src/sage_docbuild/ext/multidocs.py.orig src/sage_docbuild/ext/multidocs.py
--- src/sage_docbuild/ext/multidocs.py.orig	2021-08-22 02:44:34.000000000 -0600
+++ src/sage_docbuild/ext/multidocs.py	2021-08-26 13:11:24.937824557 -0600
@@ -84,8 +84,11 @@ def merge_environment(app, env):
             for ind in newalldoc:
                 # treat subdocument source as orphaned file and don't complain
                 md = env.metadata.get(ind, dict())
-                md['orphan'] = 1
-                env.metadata[ind] = md
+                try:
+                    md['orphan'] = 1
+                    env.metadata[ind] = md
+                except AttributeError:
+                    env.metadata[ind] = {'orphan'}
             # merge the citations
             newcite = {}
             for ind, (path, tag, lineno) in citations.items():
diff -up src/sage/interfaces/singular.py.orig src/sage/interfaces/singular.py
--- src/sage/interfaces/singular.py.orig	2021-08-26 13:11:24.940824561 -0600
+++ src/sage/interfaces/singular.py	2021-08-26 13:17:49.831262334 -0600
@@ -2370,11 +2370,11 @@ def generate_docstring_dictionary():
 
     L, in_node, curr_node = [], False, None
 
-    from sage.libs.singular.singular import get_resource
-    singular_info_file = get_resource('i')
+    singular_info_file = '/usr/share/info/singular.hlp.gz'
 
     # singular.hlp contains a few iso-8859-1 encoded special characters
-    with io.open(singular_info_file,
+    import gzip
+    with gzip.open(singular_info_file,
                  encoding='latin-1') as f:
         for line in f:
             m = re.match(new_node,line)