> I'd like to code a way to sort the bookmark list by the "last modified
> date" (i.e. not the creation date of the bookmark but last time the
> bookmark was modified).
> 
> AFAIU, the current order of the buffer list is always "last created
> first" and there is no date associated with the modification.
> 
> In order to have this feature, I could modify the default order of the
> bookmark list to "last modified first" or add a new field for each
> record with the modification date? The former modifies the default
> order of the bookmark list. The latter modifies the bookmark files format.
> 
> FWIW, I've tried doing the latter but I think I'd prefer the former as
> it would work automatically with a 'bookmark-sort-flag' to nil.
> 
> What do you guys think?

1. Please don't change the bookmark-file format.

2. You can find code for sorting bookmarks (in
   many ways) in Bookmark+.  See attached
   screenshot for the predefined ways.

Sorting bookmarks with Bookmark+:

https://www.emacswiki.org/emacs/BookmarkPlus#SortingBookmarks

 You can easily define your own sorting
 commands and sort orders.  See macro
 `bmkp-define-sort-command' and the
 doc for option `bmkp-sort-comparer'.
___


https://www.emacswiki.org/emacs/BookmarkPlus