Thank you for that helpful bit. I am super glad MATE exists and is improving, but I don't think I have a need to update it, just because. On the other hand, I am a superfan of Nautilus, and I am more than extremely glad Mint is keeping the good Nautilus alive with caja. Back in Windows, I used X2 as my preferred file manager, after years of trying whatever offerings came available. Ye Olde Norton Commander and Wordperfect file management had spoiled me for any lesser offerings. And, over the years, "lesser" became "more", iykwim.
On switching my primary desktops to linux, I looked at every file manager I could find, and NONE did the job as well as x2. Xfe came the closest. KDE's Konqueror was too heavy and lacked features, and Dolphin was too light. There are many NC copycats, but that mode is so old and dated now, that new functionality was important. I don't know where or when Nautilus gained a second pane (to my knowledge, it did NOT have a 2nd pane when I first used it), but at some point I discovered it was there. And then I was happy. It does almost everything that x2 does, and what it doesn't, I haven't particularly needed.
I MIGHT use the backports to get the latest Caja! Pass the word to the guys on that team - and the MATE team - that I will buy them a beer any time they want it. Good work!