The downloads-page looks like the last weeks - 12c is the default...
... but the documentations tab lists 18c:
blogs.oracle.com shows the following:
So the "cloud first" strategy is still in place (by the way: is this something like "america first"?).
The installation procedure looks strange:
Starting with Oracle Database 18c, installation and configuration of Oracle Database software is simplified with image-based installation.
To install Oracle Database, create the new Oracle home, extract the image file into the newly-created Oracle home, and run the setup wizard to register the Oracle Database product.
Using image-based installation, you can install and upgrade Oracle Database for single-instance and cluster configurations.
Oracle shows up this:
But there is no 18c on OTN for download...