To start, https://wiki.lineageos.org/devices/bullhead/build but you won't get 17.1 support from official Lineage sources. The most you can do is the latest 15.1 with the last ASB merge from Google, but at that point you may as well find the last official and install.
I'd recommend looking for other 'trustworthy' developers who are working on your device in the open. You can install their pre-compiled builds or you can use their sources for your own builds. There are unofficial builds of Android 17.1 on XDA [0].
I'd recommend looking for other 'trustworthy' developers who are working on your device in the open. You can install their pre-compiled builds or you can use their sources for your own builds. There are unofficial builds of Android 17.1 on XDA [0].
0. https://forum.xda-developers.com/nexus-5x/development/rom-li...