Hello Samya, 

Thanks for posting your query in PSC :)

There is no documentation on the function setAnimationAction in webwb • pzpega_ui_transitions • js. 

Below is the comment from above js file for the function.

/*
     * Sets the current animation action to take
     * @param {string} the animation action to take (left, right, up, down or refresh). Defaulted to left if not one of these.
     * @param {string} whether the animation should come into view , or go out of view. (Valid values are: in, out). Defaulted to in if not one of these.
     */

As per pzAppConfigUseTemplate and pxAppWizardButtons sections, back button is configured with below action set:

on click >> 1) Run Script : pega.ui.transitions.setAnimationAction passing value as right.

                          Run script to transition out the current content

                    2) Refresh other section (pzAppConfigContent)

                           Refresh section containing the layout to transition

                    3) Run Script : pega.ui.transitions.setAnimationAction passing value as "".

                            Run script to transition in the new content

As per pyAchievementListForUser, they run Data Transform before above 3 actions to change the context of the content to be transitioned.

Regards,

Rincy