What is the Tech Lead's Role in Agile

Most agile and scrum teams formally or informally assign a technical lead role. But what does that role mean and what are the responsibilities? In Episode 11 of Five Minutes with @NYIke, Isaac Sacolick reviews StarCIO's Agile Planning process and specific roles for the tech lead during continuous planning, agile delivery, deployment, and monitoring.

[Bobesboy]

Great concept! Bearing in mind an Agile Team is supposed to be self-organized, how can this be possible when there is no Agile Team but a Cross-disciplinary Team? Is this Cross Disciplinary Team your Agile Team? If yes, how can they work together with the PO, SM and Tech Lead as a team when Cross Disciplinary Team is a team on its own? When we say the performance of an Agile Team is a synergy the team effort of collaborative and coordinative cross-functioning: How is that possible if there is only Disciplinary Team and the rest roles are not part of the that team? There is just a lot here from my understanding of Agile does not really align.