I conducted a test using flying squid with version 1.15.2 and prismarine-web-client with 1.15.2 so that I can connect to the flying-squid server with pwc.
I then deleted all the node_modules/prismarine-viewer/textures/ files and folders except for 1.15.2 folder and 1.15.2.png. The title screen buttons and the options and connect screen background image and buttons no longer have any image assets.
With a bit of trial and error I found that putting the 1.17.1 folder back returned the screens to normal.
Shouldn't the pwc initial screens use assets from the correction version folders rather than some other random version?