Category A - raw option access

A list known to be an option list (because it is a declared option argument or is passed to a predicate that processes options) is inspected using memberchk/2, member/2 or select/3 rather than option/2. Raw list search is order-agnostic and does not honour the Name=Value form, so it may disagree with option/2 (leftmost wins) semantics.

Category B - override defeated by rightmost-wins

A partial list [Opt,...|Tail] is passed to a predicate that resolves options with PL_scan_options() (rightmost wins, e.g. open/4). The prepended options look like an override but are defeated by a duplicate in Tail. Append the option or use merge_options/3 instead.

Spec is a module or a Module:Name/Arity.