Yes, true, unless you start darktable with --library :memory:
Are you looking for a possible feature in dt where a preference setting would turn on some extra processing, namely, when you output an image, dt would also output a copy of the XMP named the same as your image. You would then have a free-standing independent record of your edits.
@RawConvert
Yes, It is. I don’t have enough DT knowledge to say what’s best, with less impact.
Another option could be a simple (I believe) flag that put a duplicate in read-only.
It is like freezing a state of work.
In this way, after a duplicate export that satisfies you, manually set the read-only flag to true.
After that you have a history that matches the export.
It’s embedded in the JPG so it really overkill…
I don’t much like the history being in the jpeg. Seems odd someone has gone to all that trouble to design a compact file, then you go and stuff data in it which is irrelevant to most people who see the image! If I send someone a box of chocolates, I don’t enclose a map showing the route I took to the shop where I bought them! Some might even argue having the history in there is a privacy concern? And correct me if wrong, but the jpeg history is not 100% reliable because tags can be too big.
@Ric_Developer , I can see setting read-only is more secure, however dt does not access XMPs with a name other than “image file”.XMP (unless you explicitly tell it to, e.g. loading an existing xmp onto an image file) so perhaps you might be worrying too much about this?
Storing the history stack in the exported image file is optional, as is the use of sidecar files. So all that can be set according to your personal preferences.
As for the size, according to the manual:
“Entries in XMP tags can get rather large and may exceed the available space to store the history stack in some output files on export”. That’s probably which is why there is an option to store them in a compressed binary format.
Maybe yes. I’ll try to find the best suitable processing flow for me.
In general I like sidecar files, but not for all files even if not edited. So I disabled “write didecar for all images”.
I’m doing some tests.
In the next version of darktable you will be able to choose only to write sidecar files when you edit an image, rather than on import.
Great !!! 
Thanks, that’s good about “only write when edit”.
@rvietor , @priort , about tags in output, the manual (3.6) also says “Users are therefore advised to not rely on this feature for their backup strategy. To back up your data always make sure to save your input (raw) file as well as all of darktable’s XMP sidecar files.” (page 195)
Same question as the post, but with a different intent: how can I quickly save an .xmp file from lighttable to a specific location, eg in /tmp/, for subsequently posting in this forum?
Currently I look up the file in the relevant folder, but this is a bit tedious.
I don’t think you can just save the xmp in a “random” place. You can however export e.g. a medium-quality jpeg with the history stack in the metadata. That jpeg can then be used as if it were an xmp sidecar to load a history.
Added advantage: users get a quick preview of what your history stack does 
I was scolded for doing this and rightly so I guess as some people apparently just want to look at the txt file…if your version is not common from building or whatever it may not load as a sidecar but they could still read the text… at least that is what I recall I was told…
So people who post xmp’s here just find them manually?
No I usually export the raw file to my desktop or download and then do the edit from there and then it saves the sidecar there too…then I just upload both and delete them…
How do you do that? (Sorry if this is obvious, but this is what my question is about.)
Sorry I edited my post…I usually edit the source files outside of my normal storage as I can be messing around or I have downloaded playraw whatever and I don’t want them in with my files…usually do all this inside my download folder…then from time to time I clear it out…
EDIT I don’t use the DT database so I just use it like any other program and open files from where ever or from my photo folders… I don’t worry too much about locations as I am not working with the database…not that that would matter but I just don’t need it…
How does one do that?
I have processed 11 different versions (minor changes) so I can compare them, but I can’t see the history stack.
exiftool:
$ exiftool dodoite-20131024-2673_11.jpg
ExifTool Version Number : 12.16
File Name : dodoite-20131024-2673_11.jpg
Directory : .
File Size : 232 KiB
File Modification Date/Time : 2022:01:19 18:18:12-08:00
File Access Date/Time : 2022:01:19 18:18:12-08:00
File Inode Change Date/Time : 2022:01:19 18:18:12-08:00
File Permissions : rw-r--r--
File Type : JPEG
File Type Extension : jpg
MIME Type : image/jpeg
JFIF Version : 1.01
Resolution Unit : None
X Resolution : 1
Y Resolution : 1
Image Width : 1500
Image Height : 1125
Encoding Process : Baseline DCT, Huffman coding
Bits Per Sample : 8
Color Components : 3
Y Cb Cr Sub Sampling : YCbCr4:2:0 (2 2)
Image Size : 1500x1125
Megapixels : 1.7exiv2:
$ exiv2 dodoite-20131024-2673_11.jpg
File name : dodoite-20131024-2673_11.jpg
File size : 237601 Bytes
MIME type : image/jpeg
Image size : 1500 x 1125
dodoite-20131024-2673_11.jpg: No Exif data found in the fileWith rawthereapee, the sidecar is created with each jpeg/tiff export (optionally).
Thanks
See develop history under darktable 3.8 user manual - export and load sidecar file under darktable 3.8 user manual - history stack.
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Use “preferences” dialog in export tool.
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