To export all of your Hypothesis annotations
Perhaps the most useful tool to export hypothes.is annotations I found so far is gooseberry. I always stored my notes as separate Markdown files and gooseberry can export hypothesis annotations in exactly that format - with a bit of tweaking of the default templates. Further tooling is also mentioned in here.
Actually, using the hypothesis BOOKMARKLET is much more convinient than 'paste a link' or typing "via.hypothes.is/" in front of every link you want to annotate. With the bookmarklet all you need to do is, when you find a page that you want to bookmark, in the search bar of the mobile browser search for the name you saved the bookmarklet as and click it. It will immediately load hypothesis on the page just like clicking the hypothesis extention would do in pc. To bookmark the bookmarklet link (which can be found in https://web.hypothes.is/start) in the mobile browser, copy the link address of the bookmarklet link (which is a javascript code) and just edit an existing (useless) bookmark already there in the mobile browser replace the url with the bookmarklet link. Also give it a title (like "bookmarklet hypothesis") which you would type in the address bar of the mobile browser to find the bookmarklet bookmark.
via.hypothes.is does not work as they stopped providing an open proxy. It makes all URL forwarders and standalone apps on Android close to useless.
The piece of advice provided here works, but it is highly unintuitive.
The mechanics is this: 1. open a page where you want to add annotation 2. click on a bookmark as if you are opening a new page 3. since the bookmark is actually just a piece of javascript, it will simply load hypothes.is client 4. profit.
To make it work in Firefox mobile, the instruction is this: 1. create a new arbitrary bookmark on some page. It will appear in the list of your bookmarks. 2. copy the bookmarklet javascript code. I was not able to do it directly in the FF mobile, so I copied it on my desktop and sent it to the phone via an IM 3. edit the newly created bookmark and a) give it a name, e.g., "hypothesize"; and b) replace the URL with the piece of copied javascript code 4. now when you want to add an annotation, follow the process above.