Permissions - Basic Questions

1) Has Microsoft changed the names they use for Principal in WIndows 10 versus Windows 7?
2) The following file (see original and new) -- prior to my messing with editing permissions --
had a line for "Trusted Installer". After playing with permissions I attempted to put "Trusted Installer" back as Owner. It appeared to succeed but did NOT show in the Principals list.
(a) Does "Trusted Installer" only exist as a Principal if no one edits permissions?
(b) Was "Trusted Installer" automatically renamed to SYSTEM?

Its still there but your looking at a file not a folder its normally on a folder which is then inherited by folders below

Thanks for responding.
Yes, per your post, I see it on the folder.
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Additional Questions
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I'm assuming this has something to do with inheritance and that anything
below (file in this case) inherits the rights from above (folder in this case).
If this is correct, is there:
1) Anyway to know this file inherits from the folder (belongs to the Trusted Installer group), by looking at the file instead of the folder?
2) Is it necessary -or- better to identify this file to the "Trusted Installer" group (which I haven't been able to do up to this point), or am I making work for myself?
3) If I just wanted "TrustedInstaller" for example) on just this file, would I need to remove "TrustedInstalller" at the folder level and then apply it to the file of interest (which I have not been able to do up to this point)?
4) If I remove "Trusted Installer" group at the folder, would all files in that folder be affected, or would I have to do each file individually -or- is there a better way to add or remove several files from a group at the folder level?