I know the project is still in flux, but just reporting my experience trying to get started on a fresh checkout.
$ make
ocamlbuild -cflag -g -no-links -use-ocamlfind client.byte test.byte
+ ocamlfind ocamlc -c -g -g -bin-annot -strict-sequence -syntax camlp4o -package lwt.syntax,irmin,lwt,sexplib.syntax,uuidm,irmin.mem,base64,ocamlgraph,reactiveData,omd -w A-4-44 -I js -o ck_model.cmo ck_model.ml
File "ck_model.ml", line 763, characters 9-27:
Warning 48: implicit elimination of optional argument ?init
File "ck_model.ml", line 768, characters 12-20:
Warning 48: implicit elimination of optional argument ?step
File "ck_model.ml", line 771, characters 18-32:
Warning 48: implicit elimination of optional argument ?step
File "ck_model.ml", line 782, characters 25-32:
Warning 48: implicit elimination of optional argument ?step
+ ocamlfind ocamlc -c -g -g -bin-annot -strict-sequence -package js_of_ocaml.syntax,js_of_ocaml,js_of_ocaml.tyxml -syntax camlp4o -package lwt.syntax,irmin,lwt,sexplib.syntax,uuidm,irmin.mem,base64,ocamlgraph,reactiveData,omd -w A-4-44 -I js -o js/ck_template.cmo js/ck_template.ml
File "js/ck_template.ml", line 283, characters 13-25:
Warning 48: implicit elimination of optional argument ?a
File "js/ck_template.ml", line 684, characters 60-73:
Warning 48: implicit elimination of optional arguments ?extensions, ?default_lang
File "js/ck_template.ml", line 684, characters 77-88:
Warning 48: implicit elimination of optional arguments ?override, ?pindent, ?nl2br, ?cs
File "js/ck_template.ml", line 854, characters 11-19:
Warning 48: implicit elimination of optional argument ?init
File "js/ck_template.ml", line 873, characters 17-25:
Warning 48: implicit elimination of optional argument ?init
File "js/ck_template.ml", line 891, characters 11-19:
Warning 48: implicit elimination of optional argument ?init
File "js/ck_template.ml", line 960, characters 51-62:
Warning 48: implicit elimination of optional argument ?step
File "js/ck_template.ml", line 961, characters 42-53:
Warning 48: implicit elimination of optional argument ?step
File "js/ck_template.ml", line 967, characters 74-85:
Warning 48: implicit elimination of optional argument ?step
File "js/ck_template.ml", line 1000, characters 7-15:
Warning 48: implicit elimination of optional argument ?init
+ ocamlfind ocamlc -c -g -g -bin-annot -strict-sequence -syntax camlp4o -package lwt.syntax,irmin,lwt,sexplib.syntax,uuidm,irmin.mem,base64,ocamlgraph,reactiveData,omd -w A-4-44 -I js -o git_storage.cmo git_storage.ml
File "git_storage.ml", line 8, characters 38-47:
Error: Unbound module I.History
Command exited with code 2.
Compilation unsuccessful after building 55 targets (0 cached) in 00:00:06.
make: *** [all] Error 10