https://bugzilla.mozilla.org/show_bug.cgi?id=1692176#c6 suggests his might be hidden intentionally, but that seems inconsistent with the behavior in a new profile where it is greyed out.
Bug 1709107 Comment 3 Edit History
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https://bugzilla.mozilla.org/show_bug.cgi?id=1692176#c6 suggests this might be hidden intentionally, but that seems inconsistent with the behavior in a new profile where it is greyed out.