Oracle have (at the regional Oracle CloudWorld event in Singapore) just announced Oracle Database 23c Free Developer Release. If you are familiar with Oracle Database, you will know all about Oracle Database XE. This announcement is effectively a replacement of what would have been Oracle XE 23, built and made available with developers in mind. Ultimately, this new offering gives developers "early access" to build new applications, enhance or upgrade existing applications using all of the new features that 23c offers.
Oracle JET – Getting Started