API docs are vague on expire_in, don't describe sig/get endpoint

In the process of writing an API client, I was looking at the [docs for login](https://keybase.io/docs/api/1.0/call/login).

"expire_in: how long this signature is good for; after it expires, it will not be admissable for login"

The example value given is 157680000, and it's unclear what format this is from the documentation. The doc page for [sigchains](https://keybase.io/docs/sigchain) says that the value in the response is in seconds. Is that how the parameter for login should be specified? If so, 157680000 seconds is equal to 5 years. Does that mean that subsequent logins may use the same values for v4 and v5 for 5 years, and is that good practice?

Additionally, the [sample call](https://keybase.io/_/api/1.0/sig/get.json?uid=9ff6c07ed195763056d0f9718a419519) from the sigchain docs linked above is to the sig/get endpoint, which is not described in the API docs as far as I can tell. Am I missing that somewhere?

Thanks!

Start with the linked login API documentation and the sigchain documentation, comparing the expire_in description and example with the stated seconds format. Verify the intended unit and usage guidance, then check the sig/get sample endpoint and document it if it is missing from the API docs; done means both questions are answered in the documentation.

Written by the indexing model from the issue text.