Pardon the necro-bump but this is still relevant. I've encountered at least two games so far (both of them 'featured' games on the main itchio page) made with RPGMaker but are in RAR format. For some absurd reason one of the devs even has a ZIP version for Mac but still RAR for Windows.
I'd like to request that non-standard patent-encumbered archival formats like RAR be deprecated and developers be prompted to compress using ZIP or 7-Zip (7Z) formats.
If 7Z format archives were mandatory-enforced then not only would download sizes be significantly reduced compared to the RAR format (saving itchio significant money on bandwidth costs) but the spread of the patent-encumbered RAR format is a clear detriment to the open-source and indie game development & plalyer communities.
The itchio desktop application can't handle RAR format anyways so that adds another issue to those devs that don't know how to just ZIP or 7Z their files.