pandoc --list-extensions vs. --from, --to

[jidanni]

When we do e.g.,

$ pandoc --list-extensions=docx
-ascii_identifiers
+auto_identifiers
-citations ...

isn't there a piece of information missing:
whether each extension is only for

• --from=docx+extension
• --to=docx+extension
• or instead, both?

[jgm]

Since these are syntax extensions, they should generally affect both writer and reader, though there are some gaps in implementation.