Welcome to the Hook Productivity Forum, @zeltak. And thanks for asking.
I’m part of the CogSci Apps team. Hook does not depend on any undocumented macOS features. (There was an initiative several years ago for tagging that used features (xattributes) in a way that some objected to. Hook does not do that. Having said that, xattributes continue to be used without problem in those types of endeavours – i am definitely not passing judgment on it.)
Of course, any third party app developer can be unpleasantly surprised by Apple. it happens from time to time and developers work around issues if they can/and are committed. Moreover, Apple’s own apps sometimes change in ways its users do not like. (Final Cut being a prime example.)
Hook has an export mechanism (Preferences > Export). So you can export Hook information. The database where Hook data are stored is not encrypted. It’s in the standard place
~/Library/Application\ Support/com.cogsciapps.hook/ .
Hook has an AppleScript dictionary, so you can browse Hook bookmarks without the Hook UI, and get data out. The dictionary is not yet complete. We are extending Hook’s AppleScript dictionary to help users / developers do more with it. There was a forum topic recently about that.
Hook’s documentation is on its website, which makes it easy for us to extend and users to get the benefits immediately: here and here , which we continue to extend.
I’ve been doing R&D in this space since 2001. (I led the software development of related multimillion $ R&D at Simon Fraser University from 2002-2009. Our CTO , a dev of ours and I have been working together on CP projects since 2003 and 2006 with some breaks in there to do other work.) I.e., the research and development projects are interrelated. I’ve also written a couple of books about this. There are multiple devs involved, and others. So we’re not just flying by here. Hook 1.x is the tip of the iceberg . CogSci Apps is committed to extending Hook in innovative ways that address key cognitive productivity challenges we have identified, such as the meta-access problem described in the first Cognitive Productivity book. I.e., we like to pleasantly surprise, rather than develop software that already exists. Without putting a specific date on it, I can say Hook 2.0 is in the works.
I don’t mean this to be the last word in the discussion, of course. CogSci Apps will publish some other relevant material too.
2020-05-02 17:17: I updated this post to mention our CTO and dev in relation to Hook’s history.