Proceeds from the tip jar go to Pan's programmers.)
Right now all the Pan efforts are focused on moving the betas along until they turn into Pan 1.0. Since 'stable' releases always get more users than betas, there will be inevitable 1.0.x bugfix releases.
Work on Pan will continue after 1.0.x, but no feature list has been decided on for 1.1 yet. Feedback and requests are welcomed via Bugzilla, the pan-users mailing list, or better yet, both.