What does the value 300 means that always appears in the RS timeline? If I have one animation with duration, why I am also able to edit (using red EDIT icon) the value at “300”?

Bart
Hi Bart,
Kindly refer to the link below
https://www.themepunch.com/revslider-doc/layer-animations-timeline/#layers-timing-sorting
Hope that helps.
Thanks Paul.