Badge logos (sometimes called button logos) are used to advertise a website’s server software or platform. Here’s a few examples:
Apache Badge Logo
Apple Xserve:
PHP:
Personally, I always like seeing badge logos because they give an interesting insight into that website: which stack is powering the website, the preferred coding language of the webmaster, etc.
Here’s logos for App Engine:
For reference, these are the equivalent badge logos for Microsoft Azure and AWS:
