I think this extension is outdated? Last updated in 2019.

It's unclear what the extension does.
"updates the diary related appearance":
To me, this reads as "diary = journal = quests".

I tested a little, enabling and disabling the extension. However, I see no difference on the Lodestone's quest pages, either on the quest list for your character, or on pages for individual quests.

I would appreciate an update or clarification, because the Lodestone is a great resource and I would love to enhance it.

@Ryuichi Sorry to leave these notes in a review - I would have gone for a personal contact, but I don't know how to reach you.