From the response to a bug report by me about a completely wrong version of mod_perl 2:
I'm afraid you will be out of luck here, if I understand the issues correctly. The official release of mod_perl 2.0 never made it to Sarge, the 1.999.21-1 packages in Sarge is a pre-release. The problem was that shortly before mod perl2 went stable, the upstream developers decided to rename lots of things in the API, and Sarge shipped the old API. Thus, mod perl 2.0 as shipped with Sarge won't run in the rest of the world, and vice-versa. Also, the documentation will be confusing. [...] So, well, this isn't a good situation, but it is something we have to live with.
What? They must have lost their minds. Once again, for clarity: the mod_perl 2 version in Debian Sarge—the current stable Debian—is not compatible with the old mod_perl 1 version or the real mod_perl 2 version because it is a 1.99something with a quite different API. Applications based on it are not portable from the old version and not portable to the new version. Anyone who wants to work with Debian Sarge, Apache2, and mod_perl must first get a backport because the version included is simply completely wrong.
This is absurd. Sure, mod_perl 2 wasn't ready for release on time, but the version currently in Sarge is simply garbage. Instead of removing it, an intermediate version is included, making life difficult for anyone who wants to port mod_perl applications to Apache 2—and doubly so, because with the next release, they'll have to port again.
And then the knockout punch last night:
The only valid complaint in this bug report is the fact that we don't include pre-2.0 API docs in sarge. Debian makes absolutely no guarantees that the version of a package shipped in a stable release will match whatever the current API is on its upstream website.
Summary: we don't understand anything and insist on behaving like complete idiots. Instead of at least removing the junk release—which is also classified as "don't use" by upstream—the missing documentation is now listed as a wishlist bug.