Cloth sheathing on ball ends of strings?

[id-man]

I bought a used guitar recently that had these wrapped-end strings on it. I didn't pay much attention to it till I went to change them, then it struck me as odd. Oh it must be some of those whatchacallits. I mean, I've seen strings like that before but not in a long time. It bugged me enough I just tried to go online and search for 'wrapped end' guitar strings, and I'm drawing blanks. Are these a known brand or could it be something the last owner did himself to stop string breakage or something?