Linkchecking gitweb's atom feed on a test repository reveals a 
(solitary) broken link under certain conditions.  I can't deal with it 
right now, but maybe someone wants to look into it?  Here's how to 
reproduce it:

1. Unpack test.git.tar.gz (attached) into gitweb's project root.

2. Make sure $feature{'blame'}{'default'} = [1]; is on in 
gitweb_config.perl.

3. Download http://localhost/.../gitweb.cgi?p=test.git;a=atom

4. Locate the following link in the atom feed: 
http://localhost/.../gitweb.cgi?p=test.git;a=blame;f=renamed_file;hb=037554ed1a38b5112181208ac5a02ab461c4d305

5. Access the link -- it yields 404.

-- Lea