We can reference values in the trigger payload using the syntax “<+eventPayload.” followed by the path to the key name. More details for the same can be referred here
Certain keywords in the payload will not be detected when we use the dot operator in the above expression as these words are reserved in the JEXL engine.
List of reserved keywords in JEXL engine : or and eq ne lt gt le ge div mod not null true false new var do while break continue function return
If we want to reference these reserved keywords with dot operator, quoted identifiers or the [ ] operator can be used, for example :
<+eventPayload.push.changes.‘new’.type> or <+eventPayload.push.changes.[‘new’].type> can be used to reference the reserved keyword “new”.
More details about the JEXL syntax can be referred here