The following bug has been logged on the website:
Bug reference: 16091
Logged by: Yuri Cherio
Email address: cherio@gmail.com
PostgreSQL version: 12.0
Operating system: Ubuntu Linux 18.04
Description:
After upgrading postgresql from 9 to 12 the following statement no longer
produces the same result: SELECT xpath('name()', '<abc>xyz</abc>'::XML)
PostgreSQL 9 returns '{abc}'
PostgreSQL 12 returns '{""}'
This behavior changed in version 11 and perpetuated into 12.