Is it possible to use an xmltv file that I serve through a webserver for guide data?
This is not possible, nor are there any plans to add such a feature.
Can you explain why you use your own xmltv data, and how you generate it?
There are several options for doing that: webgrabplus, https://github.com/tvgrabbers/tvgrabpyAPI and https://github.com/beralt/horepg. Do you grab the guide data directly from gracenote or “through” an API of the hdhomerun itself? Like the channels: http://10.0.0.9/lineup.json. Then I might be able to go through a proxy and provide it myself. With something like this https://github.com/jkaberg/tvhProxy
The guide data in New Zealand is really not that great. I would love to be able to provide my own xmltv file. I use it it Plex and it’s great but obviously Plex live tv is a long way behind how channels do it hence wanting it in channels.