I'm working on a site that has been running for few years and had different maintainers so it's kind of a mess. What I found weird is a lot of entries in
wp_postmeta where all the keys are numeric and contain a string like this:
wpAjax is the fixed part and the rest is a sequence of hexadecimal values (or so they seem). These entries are 1170 and the
meta_key ranges from 45511 to 46788 and the last post (as in the one with the greatest ID) referred to one of these meta keys is dated almost three years ago, so I think they might have been created by some plugin which has been long forgotten now.
Is there any way to find out if any plugin uses those kind of meta values? I did a search but found nothing.
I'd like to know if they're safe to delete because they seem useless and also mess up the post creation page as they fill the custom field dropdown select (I had to modify the code to exclude numeric meta keys).