Template talk:DLC ID

Obscure creation of tooltip link
I've noticed a phenomenon I can't understand.

This template uses the last 6 digits of a given FormID and adds an "xx" to the start, replacing other possible digits. It then creates a link out of "xx" and gives a tooltip. (The template uses Tooltip.) What I don't understand is the process of this link creation: All digits after the "xx" that are letters will be incorporated into the link; not for numbers.

Two examples:

I tried to understand this by looking into this template and the Template:Tooltip, but didn't find the culprit. Any ideas? -- CompleCCity (talk) 16:36, 2 February 2016 (UTC)