Somebody just found out that the source code of @langscipress books is available on the page of the books and thanked me enthusiastically.
So, in case you do not know this yet. The source code of ALL our 308 books is available on github and linked from within the books and from the langsci book page.
This is only possible since we are an #openaccess publisher. We serve science rather than exploiting scientists.
Have fun and produce good books or papers. =:-)