What is the ruling on the pre-Jumu’ah Sunnah prayer that is performed before the Jumu’ah prayer?

There is no Sunnah prayer before Jumu'ah. Rather, whoever enters the mosque should pray Tahiyyat al-Masjid (two rak'ahs for greeting the mosque), and he may offer as many voluntary prayers as he wishes, without intending a specific number. Sheikh al-Islam Ibn Taymiyyah held the view that sometimes it is better to refrain from praying before Jumu'ah, so that the ignorant do not believe it is a regular Sunnah or obligatory, especially if people consistently observe it. Therefore, it should not be consistently observed to avoid confusion with the obligatory prayer, just as Ibn al-Qayyim denied the legitimacy of this Sunnah.