Hello adrian,
Yes, you are right. Currently the Absence and TimeTracker apps do not talk to each other, so absence information is not considered for overtime calculations.
There are a large number of app integrations that we are aware of that would make sense, including the example you mentioned. But because we split our time between customers, platform development and app development, we need to prioritize hard. When more people use an app and ask for specific features, we spend more time on it.
I´ll have a look at our estimate for this feature and see if I can bump it up to be adressed soon.
Regarding contribution: I don´t think it would make sense to get outside contributions on LSW apps (apps made by Lean Softworks), as these are developed inhouse and there are lots of pitfalls and possible breakages, especially with customers using these apps. Other topics like community documentation, third-party wikis, YouTube guides, reviews or your own R3 applications definitely make sense, if you want to contribute.
I would be open to a call if you want to discuss possible options for contributing.