[DiapDealer]

Becky's got a point. Your plugin really should be excluding meta tags when it's doing it's processing. Those tags aren't relevant to your plugin's stated workflow after all.

Calibre/Kovid's reasons for what he does are immaterial to this issue. "name" is a valid attribute for meta tags, and "calibre:cover" violates no xhtml value character rules. Your plugin should not mangle them (or any existing meta tag)--especially since they're not in your plugin's bailiwick to begin with.

Your code is changing every "name" attribute it finds (in any tag) to an "id" attribute. That's just a bad idea.

Change:

#ensure all bookmarks have only 'id' attributes
for tag in soup.find_all(True):
    if tag.has_attr('name'):
        idref = tag['name']
        del tag['name']
        tag['id'] = idref

to:

#ensure all bookmarks have only 'id' attributes
for tag in soup.find_all(True):
    if tag.has_attr('name') and tag.name != "meta":
        idref = tag['name']
        del tag['name']
        tag['id'] = idref

and be done.

There's no reason for this plugin to be changing any meta tags.