When you tap in a field labelled "latin" and "verbatim" you should see a keyboard in lowercase mode. When you tap in one labelled "none", "latin-prose", or "latin-name" you should see a keyboard in uppercase mode. Eventually there will be other differences as well (in word suggestions, for example) but for now, inputmode is just controlling auto capitalization

none:
latin:
verbatim:
latin-prose:
latin-name:
none:
latin:
verbatim:
latin-prose:
latin-name: