Verification of bot_message_notification

[Question]
The docs for chat bot say

An opaque string that identifies the bot. This token should be added to all requests sent to bot_callback_url to verify that they come from Sendbird server.

Yet, I do see a x-sendbird-signature header on the callback.

Is using x-sendbird-signature possible for this? I guess bot.bot_token is the secret to be used to sign?

The x-sendbird-signature works the same way as with regular chat webhook. It still uses the API Token.