The idea of having a template to try to get the basic info needed to help is good.
But my first reaction to getting something the size of the example would be "what have this projects devs been smoking?", then I would call them [expletive deleted] and either deliberately ignore the template or just not report stuff. Something that size is self defeating.
Eleven prerequisites with seven references!!! BEFORE we get to any information. Thats totally not something that should be in the template, but sure put it in contributing or other place it will never be read.
I would have only:
1. the geany and GTK version and platform stuff first, thats essential, and 2. whats the problem, and steps to repeat, or 3. whats the improvement suggested, whats the benefit, and exactly how should it work, and "PRs welcome"
Sure there are other things we could ask, as @codebrainz did, but the law of diminishing returns and applicability applies.
I suspect a :bike: :house: may occur here :grin: