[Andreas Jung]

I _like_ tags in externals because they are self-documenting. Dealing with externals where you have several different revision numbers is a PIA since you never know what version of a module is behind the revision. You always have look through the log for the referenced module...that's very time consuming. I see this as a major risk factor when working on releases.

If you want the tag style for ZODB in Zope 2.9 and Zope trunk, I doubt anyone would yell at you if you changed them to use the ZODB 3.6 tag instead (pieces of ZODB are stitched in under lib/python/, doc/, and utilities/ in Zope 2, so that requires propedit'ing 3 directories). Because ZODB has its own advertised version number (ZODB.__version__, ZEO.version, and src/ZEO/version.txt), I always make a new tag for a new ZODB release (whether internal or external). ZODB isn't like, e.g., zope.testing in that way (and I understand why Jim would think it a pain to make a new tag of zope.testing for every little change there).