On my system the file in the user ~/Library is 25.000+ lines of XML with detailed release information and comments on lot of App Store apps. Like this:
Code:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>autoInstalledUpdates</key>
	<array>
		<dict>
			<key>__isSoftwareUpdate</key>
			<true/>
			<key>installDate</key>
			<date>2017-05-31T23:09:57Z</date>
			<key>productKey</key>
			<string>091-15298</string>
			<key>release-notes</key>
			<string>This update to Safari Technology Preview includes the latest WebKit enhancements. For more detailed information, please visit: https://developer.apple.com/safari/technology-preview/release-notes.

Use of this Apple Software is subject to the Software License Agreement for Apple Confidential Safari Pre-Release Seed Software.
</string>
			<key>title</key>
			<string>Safari Technology Preview</string>
			<key>version</key>
			<string>31</string>
		</dict>
		<dict>
			<key>__autoUpdateAbortCode</key>
			<integer>501</integer>
			<key>__firstAutoInstalAttempt</key>
			<date>2017-06-02T10:23:05Z</date>
			<key>artist-name</key>
			<string>William Modesitt</string>
			<key>artwork-urls</key>
			<array>
				<dict>
					<key>box-height</key>
					<integer>58</integer>
					<key>box-width</key>
					<integer>58</integer>
					<key>url</key>
					<string>http://is1.mzstatic.com/image/thumb/Purple127/v4/da/d9/d3/dad9d305-2075-73b6-8137-86f47f89f657/source/58x58bb.png</string>
				</dict>
				<dict>
					<key>box-height</key>
					<integer>75</integer>
					<key>box-width</key>
					<integer>75</integer>
					<key>url</key>
					
….snip…

<key>url</key>
					<string>http://is1.mzstatic.com/image/thumb/Purple127/v4/da/d9/d3/dad9d305-2075-73b6-8137-86f47f89f657/source/150x150bb.png</string>
				</dict>
			</array>
			<key>bundle-id</key>
			<string>com.modesittsoftware.Ultimate-Campgrounds</string>
			<key>current-version</key>
			<string>2.5.3</string>
			<key>description</key>
			<string>The Ultimate US Public Campground Project app shows publicly-owned, non-commercial campgrounds across the entire United States, including Hawaii and Alaska. In this app you will find campgrounds ranging from full-service locations at state parks and Corps of Engineers parks to remote boondocking and back-packing locations with no facilities or services. It is based on data from the web-based Ultimate US Public Campground Project www.ultimatecampgrounds.com. Included are US Forest Service, Bureau of Land Management, National Park Service, Fish &amp; Wildlife Service, Bureau of Reclamation, Corps of Engineers, Pacific Crest Trail, state parks and other state facilities, county and regional parks, municipal parks, utility company facilities, Indian reservations, military, Tennessee Valley Authority, non-profit (museums and conservation groups) and a handful of miscellaneous locations.  NOTE THAT THIS APP DOES *NOT* INCLUDE PRIVATE/COMMERCIAL CAMPGROUNDS, ONLY PUBLIC.

Current statistics:
Over 27,000 total campsites.
Over 4,000 of the campsites are FREE!
Over 6,000 of the campsites are $10 or under!

This app is intended for everyone regardless of their camping interests - it can be filtered by the facility owner, such as Forest Service or county. Users can also filter on camping preference, such as Tent, RV or Back-Country, or even if it has showers or not. Mark locations as your "favorite." Get driving directions to the campground.  

An updated database for this app is available approximately every month so you have the most recent and up-to-date information available.  For more info click the Support button.

Clicking on a campground location on the map shows available information about each location such as total number of camp sites, number of RV sites, number of electric hookups, whether there are showers and/or an RV dump station, fees, nearest town, phone number, elevation, web site and more. Of course the app can only show what information that can be discovered for each location.  

and so on for 25,000+ lines.

The only file in /Library/Application Support/App Store is named Adoption.plist and its contents are:
Code:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>eligibilityRead</key>
	<dict>
		<key>errorMessage</key>
		<string>ex.name (com.apple.jingle.foundation.exceptions.MZCodedException) -- ex.message (MZException code = MZFinance.AppAdoptionNotEligible, userInfo = null)</string>
		<key>errorMessageKey</key>
		<string>MZFinance.AppAdoptionNotEligible</string>
		<key>errorNumber</key>
		<integer>3552</integer>
		<key>status</key>
		<integer>-1</integer>
		<key>userPresentableErrorMessage</key>
		<string>Future updates of these apps can be found through Software Update.</string>
	</dict>
	<key>eligiblityReadDate</key>
	<date>2018-01-25T14:30:37Z</date>
</dict>
</plist>
It appears the two different App Store folders have very different purposes, but at least om my system any information about the installed apps is in the users folder 🤷‍♂️


If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein