One of the most commonly-used op_codes since basically every script checks for some form of equality. The biggest difference between OP_EQUALVERIFY & OP_EQUALS is that former does NOT push anything onto the stack. It either returns an error (if 0 or empty) or is otherwise uneventfully consumed.
OP_Code Walkthrough
Checks for equivalency, errors out if false
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Verify equality, if true (anything other than 0), do nothing, if false error out
Continue script operations