ما هو "الطلاء" الذي أباحه عمر بن الخطاب للمسلمين، والذي ورد ذكره في فتاوى ابن تيمية حول الخمر والمخدرات؟

The "tila'" (coating/paint) referred to here is grape juice cooked until two-thirds of it has evaporated. The majority of jurists hold that anything, the large quantity of which intoxicates, its small quantity is also forbidden, regardless of its substance or how it is prepared. So, if something, the large quantity of which intoxicates, is forbidden, then something, the large quantity of which does not intoxicate, is permissible. An example of this is what Umar ibn al-Khattab did when he cooked grape juice until two-thirds of it was gone, and it became like "al-rubb" (a thick syrup), and he likened it to the "tila'" used to coat camels due to its thickness. This type does not intoxicate in large quantities, and it is permissible by the consensus of Muslims. The criterion for prohibition and permissibility is the presence or absence of intoxication, not the names.