As the title suggests.
Some people maintain mods on older version for long-term support or may have been required to push an update on an old mod version because of a critical bug fix. However, this causes the latest file to be the older version, leading to the Main File being on an older version of the game instead of the latest.
The idea here is to either have the website or the owner choose which files can be the main one for whatever reason.
Alternatively, simply not having the "Main File" there would be appropriate. It is not likely to be useful to anyone. Most users want to install the mods for the specific version of the game they are playing. I can't think of any scenario where a user would intentionally choose to download a file because it's the "Main File" and get the result they were hoping for.
Attachments Open full size