One of the issues identified in the Red Hat Bugzilla performance report is that Bugzilla uses a large number of auxiliary files (mostly .js and .css). User-visible performance would be moderately improved if these files were combined (into one .js file and one .css file), so that loading a page causes fewer exchanges with the server.
<simon> jmcdonal: I'd like to delay bug 1069447. When we move to Bugzilla 4.5/5.0 we inherit that change from upstream. For us to do it now will be asking for an even bigger headache when migrating.
Currently, the upstream trunk branch has the .css files merged but not the .js files. If/when the latter occurs, this bug can be CLOSED/UPSTREAM.
Closing -- the UI modernization is expected to abandon the existing suit of .js files in favour of a new framework.