lbry.com/posts/faq/custom-ui.md

title	date
How do I specify a web-UI to use?	2015-06-21 16:00:00

If the files for the UI you'd like to use are storred locally on your computer, start lbry with the --ui flag: lbrynet-daemon --ui=/full/path/to/ui/files/root/folder

Note, once set with the UI flag the given UI will be cached by lbry and used as the default going forward. Also, it will only successfully load a UI if it contains a conforming requirements.txt file to specify required lbrynet and lbryum versions. Here is an example requirements.txt file.

To reset your ui to pull from lbryio, or to try a UI still in development, run lbry with the --branch flag: lbrynet=daemon --branch=master