Short list of notable changes in the last couple of days:
Shaper.traverse replaces deprecated Shaper.traverseTree. Just a rename.
Shaper.insertBefore and Shaper.insertAfter replaces deprecated Shaper.insertArgument. insertBefore/After are more capable and can work on sequences other than LIST (arguments), for example SCRIPT and BLOCK. They take a Ref instead of a node and pos.
Shaper.remove is a new function. Pass it a Ref and it removes it from the sequence.
Shaper.parse replaces deprecated Shaper.parseExpression. parse is smarter and does what you mean. It returns an expression/statement node or a SCRIPT if the string contains many of them. It handles semicolon as good as it can right now. Semicolon can still cause issues which remains to be solved.
Ref.prop is renamed to Ref.properties
New plugin: var-splitter. Michael this is for you. It nicely demonstrates Shaper.insertAfter and Shaper.remove.