libxmlb2 binary package in Ubuntu Focal amd64

 The libxmlb library takes XML source, and
 converts it to a structured binary representation with a deduplicated string
 table -- where the strings have the NULs included.
 .
 This allows an application to mmap the binary XML file, do an XPath query and
 return some strings without actually parsing the entire document. This is all
 done using (almost) zero allocations and no actual copying of the binary data.

Source package