The direct-message endpoints: opening the inbox and a conversation, the read-marking side effect, sending a message with attachments, and the recipient lookup that feeds the composer.
Reading the notification feed with cursor pagination, the unread-count endpoint that backs the navigation badges, and the mark-read actions, including per-type coverage and JSON payload shapes.
The JSON lookup endpoints behind mentions and the message composer: user search and content search, their single q parameter, result caps and response shapes.
Toggle-style engagement endpoints for posts, comments, gists, projects and quizzes: vote casting and removal, emoji reactions, bookmarks and poll answers, including the X-Requested-With header rule that returns JSON inst...