Tested the Downsampler Filter on Mac using IGB 10.2.0. The app is available from the App Manager and installed with no errors. The app also appears in the IGB App Store with the correct version number (0.0.3). I'm able to use the app to filter reads within a BAM file track. The instructions in the app description are clear and easy to follow. Based on the above comments, I made sure that the app's JAR files were present in the Downloads section on BitBucket. Similarly, I checked that the logo is present in the repo, as well.
All looks good to me, so I'm closing this ticket now.
New App repo has been created: https://bitbucket.org/KarthikRavee91/filter-by-down-sample/src/master/