Bug reports and other minor issues can be associated with a bounty, there is no exception for this, any issue can have a bounty.
Anyone can contribute to the bounty, Tilted Phoques will not systematically contribute to each bounty, we will contribute to what we believe to be necessary.
The bounties are handled by https://issuehunt.io/ at the moment, we are trying it out with the following issue https://github.com/tiltedphoques/TiltedOnline/issues/9 and if it seems to work out we will continue using it with higher bounties of course.