--- a/python/mozbuild/mozbuild/controller/building.py
+++ b/python/mozbuild/mozbuild/controller/building.py
@@ -1344,21 +1344,16 @@ class BuildDriver(MozbuildObject):
 
         if mozconfig['make_flags']:
             mozconfig_make_lines.append(b'MOZ_MAKE_FLAGS=%s' %
                                         b' '.join(mozconfig['make_flags']))
         objdir = mozpath.normsep(self.topobjdir)
         mozconfig_make_lines.append(b'MOZ_OBJDIR=%s' % objdir)
         mozconfig_make_lines.append(b'OBJDIR=%s' % objdir)
 
-        if mozconfig['path']:
-            mozconfig_make_lines.append(b'FOUND_MOZCONFIG=%s' %
-                                        mozpath.normsep(mozconfig['path']))
-            mozconfig_make_lines.append(b'export FOUND_MOZCONFIG')
-
         # The .mozconfig.mk file only contains exported variables and lines with
         # UPLOAD_EXTRA_FILES.
         mozconfig_filtered_lines = [
             line for line in mozconfig_make_lines
             # Bug 1418122 investigate why UPLOAD_EXTRA_FILES is special and
             # remove it.
             if line.startswith(b'export ') or b'UPLOAD_EXTRA_FILES' in line
         ]