Case-sensitive, optional.

versionMin - will be displayed as Game version: <versionMin>+

url:
If url starts with http://theindiestone.com or http://www.theindiestone.com (yes, http, not https, this is how the game reads the url key), it will be displayed regardless of other urls. Otherwise link from the last url will be displayed.

All extra keys are case-insensitive and optional.

icon - a small image that will be displayed in the list instead of the default icons.
Size depends from the UIFont.Medium height and the Font Size display option.
Without mods that change font size: default - 20, x1 - 25, x2 - 30, x3 - 34, x4 - 39.
IMPORTANT:
DO NOT add icons that are very similar to the map icon which Mod Manager displays for mods containing maps, please. It will mislead users which is against the purpose of these icons.

authors - one or more, separate each with ","

modversion - anything
NOTE:
I suggest Semantic Versioning 2.0.0, easy to understand, check it's page: https://semver.org/

tags - anything, separate each with ","