Collapse a function header.
Make NewOrigin() return an Origin, not *Origin.
Use "canonical" paths for packed archives and add New*ArchivePaths.
Drop the ArchivePaths getter methods.
Clarify some doc comments.
*set.Strings -> set.Strings.
Un-anonymize a return arg.
(%s) -> %q.
Just return the errors.
ChecksumFormat -> checksumFormat.
*set.Strings -> set.Strings.
Fix an outdated doc comment.
Drop an outdated check.
Add some missing doc comments.