Welcome to today's 10,000 (totally not trying to be offensive, learning is great).
TrustedInstaller is actually a service that was introduced with Windows Vista with the intention of preventing modification of system files. It typically is the "owner" of damn near everything in default Windows directories.
A fun way I typically show off the limitations of the system account is by telling people to try to delete a protected resource, like Windows Defender's directories. Then try it again when running with TrustedInstaller's rights and you'll possibly find yourself just staring at your screen thinking about how useful that could be.
Those leaves remind me of stinging nettles... I'm sure Gympie-Gympie is worse, but my first time being stung by nettles scared the shit out of me as they got me clear through my jeans.