This frame from the Koxx-One "Track Monster 24/26" is a top muni frame. It comes with brake bosses for Magura brakes.

• For 27.2mm seat posts
• For 31.8mm seat post clamp
• Bearing clearance: 100mm (center-center)
• 24 / 26 inch
• Black
• Weight: 1170g (26 Inch)

You need "Magura Brake Clamps" in addition to mount a brake. This frame comes with a seat tube of 29.4mm reduced by an aluminium shim to 27.2mm.