Of all open bugs, 5.9% of those in the Thunderbird product and 9.9% of
those in the Mailnews Core product have URLs. For Firefox, 12% of those
in the Firefox product and 20% of those in the Core product have URLs.
In my experience, URLs in bugzilla tend to be used to refer to one of
two main categories:
1. Here is a website explaining/demonstrating the issue.
2. Here is the specification to be implemented.
For a bug related to layout issues, I wouldn't be surprised if the URL
field contained a link to an incorrectly laid-out page instead of a
Bugzilla attachment. Thunderbird's bugs would be bad mail rendering,
which are more likely to be uploaded or privately emailed than linked to
from a URL. In addition, there is a large diversity of bugs in the
Firefox codebase which can be summed up as either "we do badly on
<insert new performance testsuite of the day>" or "please implement this
<insert random prototyped stuff>", both of which would be likely to
collect URLs. For Thunderbird, there really doesn't exist any
performance or conformance testsuites to care about, and new additions
to our underlying protocols come only very slowly--there's only 20 RFCs
in the Lemonade suite of IMAP updates in the past 5 years, which is the
largest set of useful new specifications to Thunderbird.
--
Joshua Cranmer
Thunderbird and DXR developer
Source code archæologist