NVRAM Showing Questionable Payload Variables… Can anyone verify if this is normal?

I used the terminal command in macOS ‘nvram -xp’:

    student:~ admin$   nvram -xp <?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>ALS_Data</key>     <data>     AKs=     </data>     <key>LocationServicesEnabled</key>     <data>     AQ==     </data>     <key>SmcFlasherResult</key>     <data>     AAAAAAAAAAAAAAAAAAAAAA==     </data>     <key>SystemAudioVolume</key>     <data>     VA==     </data>     <key>SystemAudioVolumeDB</key>     <data>     6w==     </data>     <key>Test_ALS_Data</key>     <data>     AQA=     </data>     <key>backlight-level</key>     <data>     2Qo=     </data>     <key>bluetoothActiveControllerInfo</key>     <data>     j4KsBQAAAAAzFEjXBbzp6g==     </data>     <key>bluetoothInternalControllerInfo</key>     <data>     j4KsBQAAMxRI1wW86eo=     </data>     <key>boot-gamma</key>     <data>     EAYAAN+cAAAAAAAAwgAAAAAAAAAMAAEGTwQDDl8MySdZLFRQ5FpXXFtnXXYff6OMHJYr     rUC5scSGz3TQ99j995Tz//zo+A4AAQesBAMOFwtQQxZGV1/CYuGHoIenneyeqabNp667     scCxxXvKM8+w0vXWmdq66T3q/fRw9f/80voQAAIIJwQEEO8JTz6PMxJK1zxVV5RIIoh4     biaagXqttECR7rp1lbDABZ3zzmaru+zuzf32n9v++YTh/vuH6P/9//I=     </data>     <key>efi-apple-payload0</key>     <data>     PGFycmF5PjxkaWN0PjxrZXk+SU9NYXRjaDwva2V5PjxkaWN0PjxrZXk+SU9Qcm92aWRl     ckNsYXNzPC9rZXk+PHN0cmluZz5JT01lZGlhPC9zdHJpbmc+PGtleT5JT1Byb3BlcnR5     TWF0Y2g8L2tleT48ZGljdD48a2V5PlVVSUQ8L2tleT48c3RyaW5nPjQ3MUE4QUI0LUVB     NjUtNEQzMC1BM0YzLURENjhFMEEwMjRBNTwvc3RyaW5nPjwvZGljdD48L2RpY3Q+PGtl     eT5CTExhc3RCU0ROYW1lPC9rZXk+PHN0cmluZz5kaXNrMHMxPC9zdHJpbmc+PC9kaWN0     PjxkaWN0PjxrZXk+SU9FRklEZXZpY2VQYXRoVHlwZTwva2V5PjxzdHJpbmc+TWVkaWFG     aWxlUGF0aDwvc3RyaW5nPjxrZXk+UGF0aDwva2V5PjxzdHJpbmc+XEVGSVxBUFBMRVxV     UERBVEVSU1xTTUNcTWFjLTdERjIxQ0IzRUQ2OTc3RTUuc21jPC9zdHJpbmc+PC9kaWN0     PjwvYXJyYXk+AA==     </data>     <key>efi-apple-payload0-data</key>     <data>     AgEMANBBAwoAAAAAAQEGAAUcAQEGAAAAAxIKAAAAAAAAAAQBKgABAAAAKAAAAAAAAAAA     QAYAAAAAALSKGkdl6jBNo/PdaOCgJKUCAgQEZgBcAEUARgBJAFwAQQBQAFAATABFAFwA     VQBQAEQAQQBUAEUAUgBTAFwAUwBNAEMAXABNAGEAYwAtADcARABGADIAMQBDAEIAMwBF     AEQANgA5ADcANwBFADUALgBzAG0AYwAAAH//BAA=     </data>     <key>efi-apple-payload1</key>     <data>     PGFycmF5PjxkaWN0PjxrZXk+SU9NYXRjaDwva2V5PjxkaWN0PjxrZXk+SU9Qcm92aWRl     ckNsYXNzPC9rZXk+PHN0cmluZz5JT01lZGlhPC9zdHJpbmc+PGtleT5JT1Byb3BlcnR5     TWF0Y2g8L2tleT48ZGljdD48a2V5PlVVSUQ8L2tleT48c3RyaW5nPjQ3MUE4QUI0LUVB     NjUtNEQzMC1BM0YzLURENjhFMEEwMjRBNTwvc3RyaW5nPjwvZGljdD48L2RpY3Q+PGtl     eT5CTExhc3RCU0ROYW1lPC9rZXk+PHN0cmluZz5kaXNrMHMxPC9zdHJpbmc+PC9kaWN0     PjxkaWN0PjxrZXk+SU9FRklEZXZpY2VQYXRoVHlwZTwva2V5PjxzdHJpbmc+TWVkaWFG     aWxlUGF0aDwvc3RyaW5nPjxrZXk+UGF0aDwva2V5PjxzdHJpbmc+XEVGSVxBUFBMRVxV     UERBVEVSU1xTTUNcZmxhc2hlcl9iYXNlLnNtYzwvc3RyaW5nPjwvZGljdD48L2FycmF5     PgA=     </data>     <key>efi-apple-payload1-data</key>     <data>     AgEMANBBAwoAAAAAAQEGAAUcAQEGAAAAAxIKAAAAAAAAAAQBKgABAAAAKAAAAAAAAAAA     QAYAAAAAALSKGkdl6jBNo/PdaOCgJKUCAgQEVgBcAEUARgBJAFwAQQBQAFAATABFAFwA     VQBQAEQAQQBUAEUAUgBTAFwAUwBNAEMAXABmAGwAYQBzAGgAZQByAF8AYgBhAHMAZQAu     AHMAbQBjAAAAf/8EAA==     </data>     <key>efi-apple-payload2</key>     <data>     PGFycmF5PjxkaWN0PjxrZXk+SU9NYXRjaDwva2V5PjxkaWN0PjxrZXk+SU9Qcm92aWRl     ckNsYXNzPC9rZXk+PHN0cmluZz5JT01lZGlhPC9zdHJpbmc+PGtleT5JT1Byb3BlcnR5     TWF0Y2g8L2tleT48ZGljdD48a2V5PlVVSUQ8L2tleT48c3RyaW5nPjQ3MUE4QUI0LUVB     NjUtNEQzMC1BM0YzLURENjhFMEEwMjRBNTwvc3RyaW5nPjwvZGljdD48L2RpY3Q+PGtl     eT5CTExhc3RCU0ROYW1lPC9rZXk+PHN0cmluZz5kaXNrMHMxPC9zdHJpbmc+PC9kaWN0     PjxkaWN0PjxrZXk+SU9FRklEZXZpY2VQYXRoVHlwZTwva2V5PjxzdHJpbmc+TWVkaWFG     aWxlUGF0aDwvc3RyaW5nPjxrZXk+UGF0aDwva2V5PjxzdHJpbmc+XEVGSVxBUFBMRVxV     UERBVEVSU1xTTUNcZmxhc2hlcl91cGRhdGUuc21jPC9zdHJpbmc+PC9kaWN0PjwvYXJy     YXk+AA==     </data>     <key>efi-apple-payload2-data</key>     <data>     AgEMANBBAwoAAAAAAQEGAAUcAQEGAAAAAxIKAAAAAAAAAAQBKgABAAAAKAAAAAAAAAAA     QAYAAAAAALSKGkdl6jBNo/PdaOCgJKUCAgQEWgBcAEUARgBJAFwAQQBQAFAATABFAFwA     VQBQAEQAQQBUAEUAUgBTAFwAUwBNAEMAXABmAGwAYQBzAGgAZQByAF8AdQBwAGQAYQB0     AGUALgBzAG0AYwAAAH//BAA=     </data>     <key>efi-apple-payload3</key>     <data>     PGFycmF5PjxkaWN0PjxrZXk+SU9NYXRjaDwva2V5PjxkaWN0PjxrZXk+SU9Qcm92aWRl     ckNsYXNzPC9rZXk+PHN0cmluZz5JT01lZGlhPC9zdHJpbmc+PGtleT5JT1Byb3BlcnR5     TWF0Y2g8L2tleT48ZGljdD48a2V5PlVVSUQ8L2tleT48c3RyaW5nPjQ3MUE4QUI0LUVB     NjUtNEQzMC1BM0YzLURENjhFMEEwMjRBNTwvc3RyaW5nPjwvZGljdD48L2RpY3Q+PGtl     eT5CTExhc3RCU0ROYW1lPC9rZXk+PHN0cmluZz5kaXNrMHMxPC9zdHJpbmc+PC9kaWN0     PjxkaWN0PjxrZXk+SU9FRklEZXZpY2VQYXRoVHlwZTwva2V5PjxzdHJpbmc+TWVkaWFG     aWxlUGF0aDwvc3RyaW5nPjxrZXk+UGF0aDwva2V5PjxzdHJpbmc+XEVGSVxBUFBMRVxV     UERBVEVSU1xTTUNcTWFjLTdERjIxQ0IzRUQ2OTc3RTUuZXBtPC9zdHJpbmc+PC9kaWN0     PjwvYXJyYXk+AA==     </data>     <key>efi-apple-payload3-data</key>     <data>     AgEMANBBAwoAAAAAAQEGAAUcAQEGAAAAAxIKAAAAAAAAAAQBKgABAAAAKAAAAAAAAAAA     QAYAAAAAALSKGkdl6jBNo/PdaOCgJKUCAgQEZgBcAEUARgBJAFwAQQBQAFAATABFAFwA     VQBQAEQAQQBUAEUAUgBTAFwAUwBNAEMAXABNAGEAYwAtADcARABGADIAMQBDAEIAMwBF     AEQANgA5ADcANwBFADUALgBlAHAAbQAAAH//BAA=     </data>     <key>efi-apple-recovery</key>     <data>     PGFycmF5PjxkaWN0PjxrZXk+SU9NYXRjaDwva2V5PjxkaWN0PjxrZXk+SU9Qcm92aWRl     ckNsYXNzPC9rZXk+PHN0cmluZz5JT01lZGlhPC9zdHJpbmc+PGtleT5JT1Byb3BlcnR5     TWF0Y2g8L2tleT48ZGljdD48a2V5PlVVSUQ8L2tleT48c3RyaW5nPjQ3MUE4QUI0LUVB     NjUtNEQzMC1BM0YzLURENjhFMEEwMjRBNTwvc3RyaW5nPjwvZGljdD48L2RpY3Q+PGtl     eT5CTExhc3RCU0ROYW1lPC9rZXk+PHN0cmluZz5kaXNrMHMxPC9zdHJpbmc+PC9kaWN0     PjxkaWN0PjxrZXk+SU9FRklEZXZpY2VQYXRoVHlwZTwva2V5PjxzdHJpbmc+TWVkaWFG     aWxlUGF0aDwvc3RyaW5nPjxrZXk+UGF0aDwva2V5PjxzdHJpbmc+XEVGSVxBUFBMRVxG     SVJNV0FSRVxNQkE2MS5zY2FwPC9zdHJpbmc+PC9kaWN0PjwvYXJyYXk+AA==     </data>     <key>efi-backup-boot-device</key>     <data>     PGFycmF5PjxkaWN0PjxrZXk+SU9NYXRjaDwva2V5PjxkaWN0PjxrZXk+SU9Qcm92aWRl     ckNsYXNzPC9rZXk+PHN0cmluZz5JT01lZGlhPC9zdHJpbmc+PGtleT5JT1Byb3BlcnR5     TWF0Y2g8L2tleT48ZGljdD48a2V5PlVVSUQ8L2tleT48c3RyaW5nPkRCOUFFQ0Y2LTg2     QzYtNDcyOS1CRTk5LUM2N0MzREIxMzgwQTwvc3RyaW5nPjwvZGljdD48L2RpY3Q+PGtl     eT5CTExhc3RCU0ROYW1lPC9rZXk+PHN0cmluZz5kaXNrMXMyPC9zdHJpbmc+PC9kaWN0     PjxkaWN0PjxrZXk+SU9FRklEZXZpY2VQYXRoVHlwZTwva2V5PjxzdHJpbmc+TWVkaWFG     aWxlUGF0aDwvc3RyaW5nPjxrZXk+UGF0aDwva2V5PjxzdHJpbmc+XDFBMzk2RjBBLTlD     NjYtMzVGMy05ODA1LTQ2RDBGNEZENjdCNVxTeXN0ZW1cTGlicmFyeVxDb3JlU2Vydmlj     ZXNcYm9vdC5lZmk8L3N0cmluZz48L2RpY3Q+PC9hcnJheT4A     </data>     <key>efi-backup-boot-device-data</key>     <data>     AgEMANBBAwoAAAAAAQEGAAUcAQEGAAAAAxIKAAAAAAAAAAQBKgACAAAAKEAGAAAAAACw     vxkOAAAAACCV+WedIUZClu42JCLFaBoCAgQDJAD3/HS+fAvzSZFHAfQELmhC9uya28aG     KUe+mcZ8PbE4CgQEmgBcADEAQQAzADkANgBGADAAQQAtADkAQwA2ADYALQAzADUARgAz     AC0AOQA4ADAANQAtADQANgBEADAARgA0AEYARAA2ADcAQgA1AFwAUwB5AHMAdABlAG0A     XABMAGkAYgByAGEAcgB5AFwAQwBvAHIAZQBTAGUAcgB2AGkAYwBlAHMAXABiAG8AbwB0     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   <data>     ZW4tVVM6MA==     </data> </dict> </plist> 

Websites that fill back button history with questionable pages

Occasionally I see links like the following (don’t visit this on your main computer) that I am redirected to on Google. The back button will either redirect back to the page, or some other questionable content. These pages are almost always some scam or phishing attempt, and I wonder how exactly do they “disable” the back button functionality? I can long press the back button to view a long list of the same exact link (this is a screenshot on Imgur), and eventually the search page is listed at the bottom (omitted for my privacy).

How do websites pull this back button hijacking off? And why does it not appear on actual search history? Is there any way to recognize this happening in the browser backend?