Thanks @BetterRead, the Version History section looks like a good way to do it.
I believe 0.7.53 was the value in the original file that I started modifying when I first began creating my plugin, so it comes from the 'demo' plugin code
interface_demo_plugin.zip. I honestly have no idea what calibre version would work for the plugin, and I'm not sure I'd even know how to test it, so I just left that field alone.
And while I'm admitting things I don't know (admittedly a lot), I also left it marked as compatible with Linux and IOS, though it's only ever been tested on Windows. I didn't do anything that I feel would make it incompatible, though I have no way of verifying that it works across all platforms. Do you think I should change it to Windows only compatibility?