Didn’t Apple actually move to SQLite for their Pages/Numbers format? I remember reading years ago that it was rocky (the transition), but was maybe eventually smoothed out?
replies(1):
$ file concessions-stand-menu-template.pages
concessions-stand-menu-template.pages: Zip archive data, at least v2.0 to extract, compression method=store
$ unzip -l concessions-stand-menu-template.pages
Archive: concessions-stand-menu-template.pages
Length Date Time Name
--------- ---------- ----- ----
58727 05-09-2022 13:27 Data/Artboard 2-26.png
26993 05-09-2022 13:27 Data/Artboard 2-small-27.png
11550 05-10-2022 08:13 Index/Document.iwa
720 05-10-2022 08:13 Index/ViewState.iwa
536 05-09-2022 12:41 Index/CalculationEngine-1686619.iwa
23 07-02-2021 17:48 Index/AnnotationAuthorStorage-1686618.iwa
43891 05-09-2022 12:41 Index/DocumentStylesheet.iwa
229 05-09-2022 13:28 Index/DocumentMetadata.iwa
17895 05-10-2022 08:13 Index/Metadata.iwa
379 05-10-2022 08:13 Metadata/Properties.plist
36 05-09-2022 12:41 Metadata/DocumentIdentifier
268 04-29-2022 22:18 Metadata/BuildVersionHistory.plist
135503 05-10-2022 08:13 preview.jpg
1666 05-10-2022 08:13 preview-micro.jpg
11057 05-10-2022 08:13 preview-web.jpg
--------- -------
309473 15 files
$ unzip concessions-stand-menu-template.pages Index/Document.iwa
extracting: Index/Document.iwa
$ file Index/Document.iwa
Index/Document.iwa: data
$ xxd -l 128
00000000: 001a 2d00 bcae 0170 6408 0112 6008 904e ..-....pd...`..N
00000010: 1203 0100 0518 c90c 2209 0a03 0a01 3010 ........".....0.
00000020: 0118 0122 0701 0b08 2e18 0109 1400 2f05 ..."........../.
00000030: 14f4 a801 0b0a 050a 030f 0111 1003 1800 ................
00000040: 2a27 daf8 66db f866 dcf8 66e6 f768 ddf8 *'..f..f..f..h..
00000050: 66df ef66 def8 66d1 f666 fdf5 66d5 f566 f..f..f..f..f..f
00000060: 8ff8 66df f866 86f9 6612 0408 def8 661a ..f..f..f.....f.
00000070: 0408 fdf5 6622 0408 8ff8 6632 0408 dfef ....f"....f2....