Defining hidden keybinding

[overideal]

Suppose I want to add some keybindings to my transient in such a way that they are not shown in the interface. What is the recommended way to do that?

[tarsius]

You could hide a group of suffixes, which all use a common prefix key, until that prefix key is pressed. See transient-common-commands for an example (but you should not use a variables as done here, define the group as usual).

There is no reasonable mechanism to hide individual commands permanently. I'm moving this discussion to the "Idea" category, because that's something I should probably implement, but I am afraid I won't get to it soon, certainly not this year.