What's the meaning of `tide ` and `LGTM ` label?

When I read this document pull request:

I see the labels tide/merge-method-squash and LGTM .

I don’t understand tide and LGTM's meaning.

The squash label tells the mergebot to squash all commits in that PR when merging.

The lgtm label tells the mergebot that you have reviewed the PR and, if you are allowed, may enable merging.

Note that PRs need to be lgtm and approved, so an lgtm alone is not enough - an approver also has to sign-off.