April Tag / Algorithms for translation and rotation from the camera

Hi all,

I plan to use the April Tag for localization purposes, therefor I found the following methods:

apriltag.rotation()

apriltag.x_translation()
apriltag.y_translation()

apriltag.x_rotation()
apriltag.y_rotation()

Where can I find the algorithms for these methods?
To the best of my knowledge, these methods are not part of the standard April Tag library?

Are there sample projects to determine the exact camera position over an April Tag?

Thank you for your answers.

Best regards,

Christoph