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

title
How do I specify a web-UI to use?

If the files for the UI you'd like to use are stored locally on your computer, start lbry with the --ui flag:

lbrynet-daemon --ui=/full/path/to/ui/files/root/folder

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