IGV currently uses zip to compress saved files (or, alternatively, stores them in raw xml). This RFE proposes adding support for other compression tools directly in IGV (see, e.g., https://commons.apache.org/proper/commons-compress/). Based on simple experiments, it is possible to achieve far better compression (almost x10) with tools such as xz or 7z. Given the rather large sizes of IGV files and the need to often archive such files on git hosts with restrictive file size limits, there is a clear benefit with better compression.