In https://www.blackmesasource.com/download.html there’s a broken link to an image.
The link shows as
<img src="https://localhost/blackmesa/img/dl-header.png" width="208" height="21">
It doesn’t show properly - unless you’re hosting a black mesa mirror on your machine, I guess 
EDIT: sorry, please delete. it’s a dup of the (still not fixed) https://forums.blackmesasource.com/showthread.php?t=12644