No official docs, no. Not yet at least, Softr still being a no-code tool 
.
It’s just a mandatory thing to make any custom code more robust.
Short story: It is linked to the loading speed of blocks in a page and how to deal with it effictively when adding custom code.
Reference: Event Listener for Dynamic Lists (React Version) - #3 by artur
(It’s not only for dynamic lists => also for static blocks).