It shows internal/technical informations of the server to OPs or the persons who have the permissions for execute the command.
This image it's what it should appear in your chat if you execute the /serverinternal command

This image it's what it should appear in your chat if you execute the /servertechnical command

This plugin it's made for the version craftbukkit 1.4.1 up to 1.7.5+ (Since no errors were found since the last releases) All the versions are compatible since 1.4.1 The recommended version it's R4 (Release 4) - B40 (Build 40) No errors were detected in this version.