For me, KindleUnpack started to unpack it before calibre gave the following error message:
Spoiler:
calibre, version 7.9.100
ERROR: Unhandled exception: <b>TypeError</b>:a bytes-like object is required, not 'str'
calibre 7.9.100* embedded-python: True
Windows-10-10.0.22631-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.22631')
Python 3.11.5
Windows: ('10', '10.0.22631', 'SP0', 'Multiprocessor Free')
Interface language: None
EXE path: C:\Program Files\Calibre2\calibre.exe
Successfully initialized third party plugins: ACSM Input (0, 1, 0) && Gather KFX-ZIP (from KFX Input) (2, 10, 0) && DeDRM (10, 0, 9) && AZW6 Image Merge (1, 1, 1) && Package KFX (from KFX Input) (2, 10, 0) && ACSM Input Plugin GUI Extension (0, 1, 0) && Barnes & Noble (1, 5, 4) && Count Pages (1, 13, 6) && Diaps Editing Toolbag (0, 4, 0) && EpubCheck (0, 2, 5) && EpubMerge (2, 18, 0) && EpubSplit (3, 7, 0) && FanFicFare (4, 33, 0) && Find Duplicates (1, 10, 9) && Generate Cover (2, 3, 4) && Job Spy (1, 0, 239) && KFX metadata reader (from KFX Input) (2, 10, 0) && From KFX (2, 10, 0) && KFX Input (2, 10, 0) && Set KFX metadata (from KFX Output) (2, 7, 0) && KFX Output (2, 7, 0) && Kindle hi-res covers (0, 5, 1) && KindleUnpack - The Plugin (0, 83, 1) && Kobo Books (1, 10, 2) && Kobo Metadata (1, 5, 0) && Kobo Utilities (2, 16, 13) && KoboTouchExtended (3, 6, 7) && Modify ePub (1, 8, 3) && Obok DeDRM (10, 0, 9) && Open With (1, 8, 3) && Quality Check (1, 13, 10) && Resize Cover (1, 2, 1) && ScrambleEbook (0, 6, 0) && SmartEject (2, 5, 0) && Smashwords Metadata (1, 0, 2)
Traceback (most recent call last):
File "calibre_plugins.kindleunpack_plugin.action", line 271, in unpack_ebook
File "calibre_plugins.kindleunpack_plugin.mobi_stuf f", line 124, in unpackMOBI
File "calibre_plugins.kindleunpack_plugin.kindleunpackc ore.kindleunpack", line 934, in unpackBook
File "calibre_plugins.kindleunpack_plugin.kindleunpackc ore.kindleunpack", line 855, in process_all_mobi_headers
File "calibre_plugins.kindleunpack_plugin.kindleunpackc ore.kindleunpack", line 632, in processMobi7
File "calibre_plugins.kindleunpack_plugin.kindleunpackc ore.mobi_dict", line 200, in getPositionMap
UnicodeEncodeError: 'utf-8' codec can't encode characters in position 0-1: surrogates not allowed
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "calibre_plugins.kindleunpack_plugin.action", line 273, in unpack_ebook
File "calibre_plugins.kindleunpack_plugin.utilities ", line 105, in showErrorDlg
File "traceback.py", line 183, in print_exc
File "traceback.py", line 125, in print_exception
File "traceback.py", line 982, in print
TypeError: a bytes-like object is required, not 'str'
OTOH, I seem to remember it being mentioned that the Mobi dictionary format was not the same as the standard mobi format.
Edit: Just for the heck of it, I copied the English-English Wiktionary file into /documents/dictionaries on my Paperwhite 10th gen. It showed up when I displayed English dictionaries and I was able to select it. A word lookup from within a book worked. All in all, I would say the dictionary does work on a Kindle.