Earlier quoted context omitted.
As much as I dislike Oracle's biz practices (I'd not touch their db product with a stick), they do a lot of FLOSS devt: https://opensource.oracle.com/ (almost endless list) But then they have take FLOSS projects and abandoned them, see OOo for instance: https://en.wikipedia.org/wiki/Apache_OpenOffice#/media/File:...
Looking through that list, most of the big projects (OpenJDK, Mysql, Opengrok) were inherited as part of acquisitions.
https://blogs.oracle.com/linux/post/oracle-is-the-1-contribu...
XFS is really important for (their) database performance, so quite a lot comes out of Oracle for it. You might also know that btrfs began at Oracle.
https://www.google.com/search?q=oracle+blog+xfs
https://en.wikipedia.org/wiki/Btrfs
"Chris Mason, an engineer working on ReiserFS for SUSE at the time, joined Oracle later that year and began work on a new file system based on these B-trees."