- Fix \Appendices command.

- Create float for code.
- Adjust fallback font weights.
- Redefine Center environment to eliminate extra space.
- Create TblrEnviron for code.

packages/CrossRef.sty

@@ -64,8 +64,8 @@
 	\@@_heading:nnnnn {subparagraph} {#1} {#2} {#3} {#4}
 }
 
-\NewDocumentCommand{\Appendices}{}{
-	\@@_heading:nnnnn {part} {\c_true_bool} {\c_false_bool} {Appendices} {
+\NewDocumentCommand{\Appendices}{t^}{
+	\@@_heading:nnnnn {part} {\c_true_bool} {#1} {Appendices} {
 		\c_@@_appendices_label_str
 	}
 }