This is fix for stretched virtual background image in case of non-standard camera aspect ratios. Image covers container instead of stretch.
meteor-compiled.js can be used to check PR on the 2.4-RCx versin of bbb. Just place it to /usr/share/meteor/bundle/programs/web.browser/ and rename it to js name file, that is already in this folder (for example, in my case this is 84b8d333cea4cfc84db4f0ebe095faa27b630d95.js). My sure you have correct permissions to this file (444).
Other sources is for pull request. Archived. PR was approved to the develop branch of 2.4.x bigbluebutton