I'm used to "research proposals" being purely focused on future plans and specific research aims, and not a place to talk about myself. However, now I'm making an application for a postdoctoral fellowship which asks me to submit only three documents: my CV, a cover letter, and a 4-page research proposal. In my previous applications of this kind, there were additional documents that explicitly asked me to justify why I want to work there, what my previous accomplishments are, etc. but this one doesn't have any guideline.
Is the research proposal an appropriate place to try to sell myself and talk about my experience? Or should all of this be contained to the cover letter? I would appreciate any insight about what the typical expectations are regarding this.