At the weekend I had some minutes and did a follow-up on the PDFreaders buglist. I just clicked on some bugs, checked if they still contain the advertisement for non-free software. If they do, I follow the existing Follow-up Guide. If they do not see any advertisement I do the following:
This way, I fixed 7 bugs for Germany. Now we have 113 out of 561 reported bugs fixed (= 20%) and worldwide 546 out of 2084 (= 26%). It helps us a lot if you do the same!