"Managers of Scrum teams"
agilealliance.org/glossary/scrum-of-scrums/ displays the following:
A technique to scale Scrum up to large groups (over a dozen people), consisting of dividing the groups into Agile teams of 5-10. Each daily scrum within a sub-team ends by designating one member as "ambassador" to participate in a daily meeting with ambassadors from other teams, called the Scrum of Scrums.
Depending on the context, ambassadors may be technical contributors, or each team's Scrum Master, or even managers of each team.
The Scrum of Scrums proceeds otherwise as a normal daily meeting, with ambassadors reporting completions, next steps and impediments on behalf of the teams they represent. Resolution of impediments is expected to focus on the challenges of coordination between the teams; solutions may entail agreeing to interfaces between teams, negotiating responsibility boundaries, etc.
The Scrum of Scrum will track these items via a backlog of its own, where each item contributes to improving between-team coordination.
Also known as a "meta Scrum".
I've started expanding my scaled skills (studying towards SPS), and came accross this. While I appreciate Nexus isn't the same as "Scrum of Scrums" (which I've seen "promoted" as part of SAFe), the question I have is this: what does the "managers of each team" refer to? Cause to me it seems like they're stating each Scrum team has a manager.
As you stated and my knowledge of the Scrum of Scrum/meta Scrum concept is from SAFe. I admit that I am not completely versed in SAFe because I've had a need to be. However, I had this page bookmarked from some research I did into SAFe.
It is also pretty widely acknowledged that even in Scrum there is a need for someone to help individuals navigate the path of career development in an organization. So, as it says "depending on the focus" I can see where a manager might be included. If the Scrum of Scrums is discussing strategy for solving problems based on new information a manager could contribute by helping to identify individuals with the skills or desire to learn the technology needed.
That is just one suggestion off the top of my head but given time, I could probably come up with others. Whether we want to admit it, companies of today are going to have managers. The corporate world is too rooted in hierarchy to change easily. Most compensation schemes are based on levels of titles (i.e. Junior Engineer, Engineer, Senior Engineer, Principle Engineer, etc) and to ensure that those levels are applied correctly and that every individual has a fair chance at progressing, there has to be someone responsible for that. The Manager role is how that occurs.
If Scrum Teams are not self-managing, they are not yet in a position to scale.
Scrom of Scrums (SoS) appears in a few scaled up frameworks (e.g. Less, Scrum@Scale, SAFe).
As I see and use it, the forum first priority is to support the teams. Even the best self-organized teams need support (and I have a couple in my group). For example, someone team require more lab equipment in order to increase its progress. The team can't solve that and therefore put that on the 'escalation board'. The SoS comes along and a manager can allocate the budget for the team. Another example is that they need to have a contact person for product X and they have no idea which team support that product. A manager in the organization might have an idea or help find someone who knows. Those are just coue of examples.
As SoS should support the teams, I would bring anyone that can help into this meeting, and managers as servant leaders can help.
This is my view. Hope it helps.