An Eclipse Mylyn connector plugin, including a patch not available at the published update site, is available at https://github.com/teknodan/mylyn-gitlab.
I have been round and around in circles trying to work out how to get this installed and running in my Eclipse installation, without success.
Any help would be appreciated.
Update:
As suggested, I can install from https://raw.githubusercontent.com/teknodan/mylyn-gitlab/gh-pages/. I can also build using maven and install from the resulting target update-site zip.
However, in both cases, the plugin behaves as if it were using the unpatched version. Specifically, when adding a new task repo, it performs validation which goes on for a long time (an hour) and fails with an error about a 50,000 API call limit. Wireshark shows lots of traffic to gitlab.com, with one burst of traffic every 5 seconds.
If I use Eclipse PDE to test the plugins in a debug Eclipce instance then everything works as expected!
I realise that this has wandered off the original topic.
As pointed out by @greg-449 and @howlger, what I needed to do was build it myself using maven (mvn package) and then install using the site archive in de.weingardt.mylyn.gitlab.updatesite/target.
I'm not quite sure why I had to bump the version numbers (to 2.2.0.qualifier). I also had to configure the main pom.xml version as 2.2.0-SNAPSHOT and the <parent> version for the child POMs. Perhaps I could have got away with less if I had done a mvn clean first.
But all in all, it is now working. Thanks to all.