I posted a pic, do I have to draw ya a picture too!?
It's relevant in that stuff happens to _everybody_ sooner or later. A Walther P99 had a PMC case failure on a local range here and it cracked along the same lines as the one above, but held together.
Some Swiss cops had their new SIG P229s fracture slides and bounce pieces off the shooters just like some US military Beretta M9s did... Baltimore County PD broke 52 of their SIG P226s... HK USP compacts have been breaking firing pins for years... all excellent guns too.
Glocks do break. For a variety of reasons. So do other guns. You can worry/post excessively about it like they do on this forum, or just ignore/ live with it like they do on the other forums.
We don' need no stinkin' kB FAQ and/or primer no more than nobody else does! ;b