It doesn't look like any of the examples here are runnable either:
https://pkg.go.dev/github.com/urfave/cli

Am I missing something? Are we sure the problem is related to the /v3 suffix?

is it a difference between package thing and package thing_test ?
Though I'm unsure which should work, since urfave/cli has them all in cli_test, nothing shows while mine in https://pkg.go.dev/go.seankhliao.com/testrepo0310/v2 only the _test one shows

I believe @seankhliao is correct. The "v1" testable examples are in the cli package rather than the cli_test package, which also prevents the examples from being runnable. Check out the "NoAction" example here and the corresponding test code here.

For "v3", the testable examples were moved into the cli_test package, but are also not runnable (seemingly because they have a major version suffix).

Thanks, unfortunately this has to go into our backlog, as we don't have resources to work on this right now.

I think this may actually be a bug (or missing feature) in the go/doc example parser. I created a playground example that uses doc.Examples to parse a "playable" example from a test that imports a package with a major version suffix: https://go.dev/play/p/V8RY15XlJZy

Notice that doc.Examples is not able to create a "playable" example when the package ends in v3 (instead of cli) unless you specify an import alias. Since the major version suffix is a requirement for v2+ Go modules, it seems like the go/doc package should know how to handle them.

I noticed a similar issue on https://pkg.go.dev/github.com/keep94/sqroot/v2. The examples in this package don't have a run button even though the v2/example_test.go file is in the sqroot_test package and imports "github.com/keep94/sqroot/v2" However https://pkg.go.dev/github.com/keep94/sqroot, the v1 version, has runnable examples.