My memory about this may be a little hazy, but in Hugo’s render method there are two entities that is serialized (and not parallelized) and have a deterministic order:
- Site (aka language)
- Output format
all output formats for a site is the union of all output formats set in config and front matter, ordered by weight (and then name). So, if you create a output format with a large weight value and then create a template for that for, say, the home page – that will pretty much be the last thing to be done.