Don't need to backup/restore translation files, this fixed upstream.

debian/rules

@@ -7,15 +7,6 @@ export DEB_LDFLAGS_MAINT_APPEND = -Wl,--as-needed
 %:
 	dh ${@} --buildsystem cmake --parallel --with quilt
 
-override_dh_auto_configure:
-	mkdir -p $(CURDIR)/debian/bak/pcmanfm/translations
-	cp -r $(CURDIR)/pcmanfm/translations/* $(CURDIR)/debian/bak/pcmanfm/translations
-	dh_auto_configure
-
-override_dh_auto_clean:
-	-cp $(CURDIR)/debian/bak/pcmanfm/translations/* $(CURDIR)/pcmanfm/translations/
-	dh_auto_clean
-
 override_dh_install:
 	dh_install --exclude=pcmanfm-qt.1 --fail-missing  --list-missing