Been cleaning up my PC and noticed I'd lost a large amount of space on my C drive. Using WinDirStat to get a listing of disk space usage I noticed that my Mozilla/Firefox/Profiles/XXXX/storage/temporary folder had grown to 4GB! Inside this folder are countless folders mostly starting like 'file++++I++Projects2015+WebGL_Builds+index.html'. Inside which is a folder called 'asmjs' that contains a number of 'module' files. Its clear to me that most ( over 95% ) of the space used here is from running Unity's webgl builds of various test projects I've made over the last year or so. So this is obviously some form of cache or maybe a local store of pre-compiled/optimised js of the webgl Unity projects ( games etc). The problem is clearly that these files are not getting cleared and are anything but temporary. As far as I can tell there is no means to control the overall size of this folder, or to clear it. At 4GB its taking up 1/16th of my C drive, so its space I cannot afford to lose. I have tried clearing all caches Firefox provides access to, i've cleared history and other storage. I've investigated IndexedDB, local storage, session storage but all were dead ends. I've made several google searches but found almost nothing on this or any useful information. I'd be very grateful to learn how to 1. Control the size of this folder 2. Delete all the content from this folder, besides simply deleting via the Windows explorer. In addition what is the best method to report this to Mozilla, as it seems obvious to me that being unable to control or that this folder can grow to 4GB so easily that there is an problem here that needs to be addressed. Thanks