Where is the main html page
Did you see this note in the installation section:
IMPORTANT NOTE: If you need to change any files then you need to do these in the run time version (e.g. in the /var/www/html folder or /etc/raspimjpeg). Changing files in the RPi_Cam_Web_Interface folder has no immediate effect. These are just copies used during the install.
Ok but I do not find in the / var / www / html folder the file that is displayed when you access the interface from the browser
Can't you just use grep to find some text from the page?
Do something like:
$grep -ri "some string from the webpage that's unique" .
That will turn up any files that contain the string "some string from the webpage that's unique".