... only the maindeveloper can repair it ? if other developer understand this code, can he repair and publish this plugin again ?

"This plugin is unclaimed or has no maintainer"

Any current developer can claim it and update it if they would like, but not everyone has infinite amounts of time or the motivation to do so.

... i can fix it, can i claim  ?

If you submit your own plugin that is accepted, you are welcome to submit a claim for this one.

hello, can somebody send me the original .cs - File of this PlugIn https://umod.org/plugins/kd-gui or can somebody repair it ? it runs on my server but if player rejoin the server, i must reload the plugin for showing ... any idea to fixed the problem ? i pay with good food or a beer :D