Lighttpd web server with dwww and related tools to display all various installed documentation file formats and search their contents (Ubuntu Trusty OS). Note the app starts under '<URL>/dwww'.
Tag "base" has the webserver & search engines but no particular docs installed other than defaults. You can start the server with:
/usr/sbin/lighttpd -D -f /etc/lighttpd/lighttpd.conf when ready or start interactively and commit your own doc installations. See the Dockerfile for more.
Tag "coredev" has gnu / linux, C, and C++ docs installed and indexed, and starts lighttpd as shown abaove. Launch e.g.:
docker run -h rtfm -d -p 80:80 seanchannel/rtfm:coredev