This module was meant to help convert the deprecated XEP-0156 TXT records into JSON format.
$ prosodyctl mod_auto156 example.com [another.example ...]
{"links":[{"href":"https://xmpp.example.com/bosh","rel":"urn:xmpp:alt-connections:xbosh"}]}
...
With the plugin installer in Prosody 0.12 you can use:
sudo prosodyctl install --server=https://modules.prosody.im/rocks/ mod_auto156
For earlier versions see the documentation for installing 3rd party modules