some papers are missing .html & .jats & .xml versions

Could someone explain to me why some papers here have only a .crossref.xml & a .pdf file? e.g. joss.02287 most other papers have .crossref.xml .pdf .html .jats & .xml It's not a blocker for me, I can work around it, but having noticed it I thought I'd point it out as an issue that someone could fix at some point (probably not a high priority I'm sure...)