Once again we see two paths, 'maker' and 'manager'. Levels go from 2 to 8 (with management roles from 5+). These align with wider company seniority levels - the holy grail of growth frameworks.
Meetup just released their engineering ladders, alongside a great writeup of how they came to be. What's interesting here is the definition of a 'product engineering lead' - a role not associated with seniority (it isn't a title).