As far as I understand, in the Brazilian Congress there is an elected rapporteur in each of the Chamber of Deputies and the Senate fo each area of government business - a sort of lead Deputy or Senator who reports to Congress on that subject.

Capítulo here does not mean 'chapter' (as in a book) but subject or matter, and in my view does not need to be translated. So we have 'rapporteur for the budget', 'rapporteur on taxation', etc There are lots of Google references to 'relator do orçamento'.

Prozians who are more familiar with the Brazilian Congressional system may be able to comment more knowledgeably.