It has no purpose, just ignore that it's there.

Cheers

OK, thank you, Ignored will be... :D

Yep, just leave the one you have where it is.

Something else... I'm using the Evocamp Theme quite modified, is it necessary to replace my actual files with new ones?

Just replace the files in the upgrade download ( except for that htsrv one )
It's best practice to back up all folders and files that are being updated as this would give the opportunity to re tweak any of the new files with any changes you may have made to those files.

I have a non standard skin and the upgrade hardly changed a thing