That's ok. There is no defined default dev process for all open source projects. Everyone has their own processes.
As Spark's and its plugins' code is publicly available via igniterealtime/Spark · GitHub it is best to do changes in Git repository in your personal branch and then do a pull request to the master branch. Then someone will apply the changes (ideally it would also need a review, but currently there is no developer to do this, so quality assurance will be only testing after building).
As there is no team or at least a project lead behind Spark currently, there were no official releases for years. But every change is incorporated by the automatic build system. Wolf's change is in the 2.7.0 #666 build Spark - INSTALL4J 666: Build result summary - Atlassian Bamboo . You can download this particular build by going into Artifacts > Install4J and select 2_7_0_666.exe (not the online one). Or you can go to this project's home page and download the latest build (#668 at the moment) Spark - INSTALL4J: Plan summary - Atlassian Bamboo . I'm using 667 build in my network currently (668 had a minor fix for the building, so not worth upgrading and it should work the same as 667). Actually i suggest using 667 as it has a neat fix for the systray icon behavior.