The main call for position papers made it seem like these were the foundational documents for discussions, and should elaborate a particular part of foundation or platform strategy. But the Writing Tips page makes it seem like we're writing the cover letter for a resume, it's all about the candidate. But these will be blinded! I'd think you wouldn't want to encourage the proposer to write, "you should select me because I'm the Lead Engineer for Kiwix" (say), since that's pretty much breaking the blinding process.
Some clarity would be helpful. The best way might be to offer a sample 100 word position paper that the program committee would agree is the sort of thing they are looking for (even if it describes some made up person or strategy or feature or whatever).