https://www.privacyguides.org/en/notebooks/?h=notes#criteria
Standard notes seems to break the 3rd criteria (Must support exporting documents into a standard format.) and (at least partially with pro version) the 1st criteria (Clients must be open-source.)
https://old.reddit.com/r/StandardNotes/comments/fwexqt/exporting_notes/fmollvp/
Nothing I’ve come across can handle the text files Standard Sheets creates, although I have not dug deeper than trying to open them with Gnumeric and LO Calc. My understanding is you’re locked into an Extended subscription forever if you want to keep using that.
https://old.reddit.com/r/StandardNotes/comments/fz0h4k/standard_notes_locks_you_into_a_perpetual_license/
The editors, it turns out, are proprietary (but with source available). You can move data away from SN and not host it on AWS, but you can’t move your data anywhere else and keep the spreadsheet functionality. It’s a lifetime lock-in for something that doesn’t work and they aren’t prepared to fix.
They seem to use potentially non-open source editors while hiding the fact from the consumer behind a FAQ
https://old.reddit.com/r/StandardNotes/comments/fsdomf/what_are_editors/
https://standardnotes.com/help/77/what-are-editors
Derived editors are derived from either open-source or commercial software projects. After studying a product and deciding it would offer a compelling user experience for Standard Notes, we first acquire a commercial license to use the product (or use the open-source license if applicable). We then study the source code and network behavior of each software we license to ensure there is no unwanted behavior. Then, we build a small wrapper on top of the product, which allows the editor and Standard Notes to communicate between each other to save data in a permission-based, controlled, and isolated manner.
There are four editors in this category: Rich Text, Markdown, Spreadsheets, and Code. These are editors that we do not build, maintain, and improve on directly. When you have a feature or issue for one of these editors, there’s a low likelihood that we are able to act on those features. Rather, we would likely work together to forward the issue to the software maker. We do however keep this software up to date with vendor releases.
https://old.reddit.com/r/StandardNotes/comments/fsdomf/what_are_editors/fm0w392/
Note that you will not find any mention about derived editors here Features | Standard Notes
(I put link in code because of the limitations for new user)