https://github.com/storytold/photocraft (inspired by Photoshop)
https://github.com/storytold/wordcraft (inspired by Word)
https://github.com/storytold/pdfcraft (one of the more mature apps)
https://github.com/storytold/vectorcraft (another app close to 1:1 parity)
(etc.)
Using REA for something as high profile as what we're doing is likely to result in lawsuits. We're doing everything we can by the books.
We cannot look at Adobe sources. Use of Ghidra is disallowed.
REA is probably great for personal apps and for abandonware, but I think if you publish the results and it's found to have decompiled the original proprietary sources in discovery, you might be in for a bad time.