Is there a quota for the number of placements from YPP internal roster?

Yes. The number of placements from the “YPP internal” roster is subject to paragraph 51 of General Assembly report A/65/305/ Add.4, “…10 per cent of the total pool of positions available for the programme [will] be earmarked for successful G-to-P candidates, who [can] be placed in any available post”. YPP internal candidates will be offered positions on a first come, first served, basis until the quota is met.