By having the leading `/` infront of the `*` makes these types of files relative to the directory the gitignore is in. If you create a Unity project inside of a git directory Unity forces you to create a new directory, thus not picking up these files.
Sysinfo.txt is generated by unity if occurs any crashes. The content consist of users system information, running process etc. I don't think that should be shared with others.
Unity only generates project files in the top-level directory.
However, the current .gitignore will ignore all project files even
if they were not generated by Unity.
It is sometimes necessary to include non-Unity project files for
level editors or other utility projects that have been added to the
repository.