https://stackoverflow.com/questions/15714809/get-filesystem-path-of-installed-composer-package if we had a "composer" object

if ( is_readable( "$IP/vendor/autoload.php" ) ) {
	require_once "$IP/vendor/autoload.php";
}

We could keep track of it at this point, but it doesn't help for extensions own vendor dirs...

I don't really want to brute force it either

Reflection feels hacky too, but would work, ish.

reedy@ubuntu64-web-esxi:/var/www/wiki/mediawiki/core$ php maintenance/eval.php 
> $reflector = new ReflectionClass('Composer\Autoload\ClassLoader');

> echo $reflector->getFileName();
/var/www/wiki/mediawiki/vendor/composer/ClassLoader.php
> echo dirname( dirname( $reflector->getFileName() ) );
/var/www/wiki/mediawiki/vendor

TBH, I feel like I'm overlooking the obvious

There is, of course, the option of getting the videojs guys to add something that Composer can autoload, and use that to get the paths...

Dunno if they'll let me add something like that.. Extra maintenance burden ;)

@Reedy upstream videojs seem to accept everyones patches, it's depending on if it will be used or good that depends on if upstream will accept it.

You could try and see if upstream will allow it.