Webmentions requires receiving x-www-form-urlencoded data. Why they chose this convoluted and complexity increasing way is beyond me. Embedding (or encoding) it in the URL string itself would've been infinitely easier for everyone with no downsides. But no, with x-www-form-urlencoded variables you need to actually be doing some dynamic scripting to handle it. If not actually some script listening for that location/endpoint then at least a series of complex nginx directives and modules to get x-www-form-urlencoded logged with all the rest of the request. This additional complexity makes running a static website that supports indieweb standards like a tail wagging the dog in terms of the webmentions receiver's relation to the static http site.
microformats2 h-entry markup is cool though. Just using class names for html elements to make some info parsing "standardized".