4 ms·

This is correct, at least for excel and word (xlsx and docx, respectfully, dont know about the others). And past the zip, theyre both largely terse xml under th

This is correct, at least for excel and word (xlsx and docx, respectfully, dont know about the others). And past the zip, theyre both largely terse xml under the hood abiding by a published schema. This is actually pretty convenient and allows for cross platform tools for creating/consuming files. For instance, I like the xlsxwriter Python module for creating xlsx files (no affiliation with the project, but I've used it at a couple of jobs to create some pretty nice spreadsheets, with no need for an excel install on a server). A lot of early Python modules required an Excel install and worked over COM, so on both accounts, Windows only.

vram22 7y ago
Yes, good points. I think (but not sure) that the change from MS Office binary file formats (with their issues of being proprietary, undocumented, etc.) to zipped XML formats (for Word, Excel, Powerpoint, etc.) came at the same time as when they added an "x" to the filename extensions, like changing .doc to .docx, .xls to .xlsx, and so on. This was also probably around the time when there was that big public hoo-ha about MS XML formats vs. Open Office / Open Document formats. I had read some about it at the time, don't remember the full details.