The computer game Anarch HD is published as a single executable file. 0install normally downloads archives but it can download individual files using the “file” tag documented in Retrieval Methods.

For Anarch HD, the resulting file is not executable. The 0install “file” tag can fix that by setting the attribute “executable” to “true”. Unfortunately, every version of 0install I’ve tested so far fails to do that; the downloaded file remains not-executable. You can correct the problem manually by going into the cache and manually marking the option, but in its current state the Anarch feed I’ve written is bugged.

In cases like this—when 0install “should” work as documented, but fails—I’ve chosen to keep the resulting feeds in their non-working state with everything else as correct as possible. Even a non-working feed remains a good reference point for how to find, build, and run past and current versions of a package.