The package has a new name merlin-eldoc. Available here: https://github.com/Khady/merlin-eldoc
Also it has been released on melpa so it is now easy to install: M-x package-install RET merlin-eldoc 
.
Since the first version:
- from 50 to 500 lines of elisp
- display type and/or doc of value at point
- highlight occurrences of value at point
- display a hint with type and/or labels expected while calling a function
- integrate with eldoc, so it is not a minor mode and it respects eldoc configuration options
- support reason syntax
- many configuration options to choose the shape and the verbosity of the output
The exact list of changes is at https://github.com/Khady/merlin-eldoc/blob/master/CHANGES.org
Latest demo (without all the fixes, but with all the features):
I have been asked how it compares to what is provided by lsp-mode and lsp-ocaml. I find that merlin-eldoc is way more polished. For example it keeps the documentation as ocamldoc rather than markdown, it highlights the types, it can reformat type and doc to fit one line, … It also offers more configuration options. But they are not exclusive, it is possible to use lsp-ocaml + merlin-eldoc (+ merlin too if you miss commands like merlin-destruct).