Taking a serious engineering team as example (ie one doing something innovative rather than cutting variants of the same code all the time) the leader has to be

Taking a serious engineering team as example (ie one doing something innovative rather than cutting variants of the same code all the time) the leader has to be an engineer. Not necessarily the best in the team but they have to get the mechanics and prognosis of technical decisions in order to manage risk, know where or who the problems are, make trade offs, etc. I've often seen the non technical leader adopt a technical right hand who defacto does the leading whilst the alleged leader reports up, administrates and generally takes credit. Further like someone else said, leading and managing are like chalk and cheese (superfluously similar). A project manager may happily be non technical because there job is mostly triage, comms and tracking.