Keep an open mind. Just because you know of only one type of HTTP server doesn't mean it's the only one. Take a look at all the HTTP servers available in this list via Wikipedia:
There are more than this and often servers just as Jetty, JBOSS, Tomcat, and many others can be dual purposed to serve static content as a HTTP server as well as serve as an application server.
List via wikipedia
With your edit I think your point is that Apache (the tag) could be associated with both the HTTPD server and the overarching project + the Apache Software Foundation.
I think part of the confusion is that most people associate the apache with the HTTP web server sub-project vs. anything else. For example I think most people would be surprised that Tomcat (another subject) is in fact called Apache Tomcat.
I think part of the confusion stems from Ubuntu (assuming Debian does the same) packages the HTTP server with an executable called
What to do?
I think I would be inclined to reorganize the tags so that apache is used as a tag for Apache related items (software, licensing, foundation), while httpd and a synonym tag apache-httpd were used for actual HTTP server related items.
I dislike making apache a synonym for httpd since it can span multiple pieces of software.