This is what chatgpt told me:
Keyboard modifications are not permitted in the Jolla Store primarily due to concerns about system integrity, security, and compatibility with Sailfish OS updates.
Sailfish OS’s keyboard layouts are deeply integrated into the system. Modifying or adding new layouts typically involves altering system files, such as those in
/usr/share/maliit/plugins/com/jolla/layouts/and configuration files likelayouts.conf. These modifications can conflict with system updates, potentially leading to broken functionality or overwritten customizations. Additionally, some custom keyboards may require additional fonts, which can further complicate system stability.Furthermore, Sailfish OS has implemented sandboxing for applications to enhance security. Disabling sandboxing is not allowed for apps distributed through the Jolla Store, limiting the ability to implement custom keyboards that require elevated permissions or direct system access.
While developers can create and use custom keyboards on their devices by enabling developer mode and manually installing them, these cannot be distributed through the Jolla Store due to the potential risks and conflicts mentioned above. Instead, such customizations are often shared via community platforms like OpenRepos, which operate outside the official store’s restrictions.
I think that is actually quite a good answer!