doublevr On the website, the Jav toggle adds 4729 videos, while there are 5953 videos with a Jav tag. Same situation in the app based on the number of results pages. If you search NOT Jav tag, the Jav toggle still adds approx. 200 videos. So the Jav tag should have all Jav minus 200.
There are also about 1000 videos with tags 'Japanese idol' or 'Japanese uncensored' but these are neither affected by the toggle nor have a Jav tag.
And the issue that seems to be unsolved for a long time is that in the app the Jav toogle switches itself off whenever you leave the 'Videos' submenu, e.g. when you go to playlists or do a free search and then go back to 'Videos' you will find the toggle in off position.