MTP (the same protocol Android devices use) will expose the /home/nemo folder to the connecting computer, both to graphical and command line applications. But it hides some files and folders from the connected system. A more powerful way is to connect through a terminal via SSH, as explained here.

There are other approaches to this involving udev rules to unlock & mount every time you insert/remove the card. This is different - the idea is that the memory card mostly stays where it is and that apps can rely on it being mounted. Manual un/mounting, removal and insertion, is still possible though.

There are some apps in Openrepos which do not seem to work anymore for SFOS 4.x. But you don't really need an app, all you need is a systemd timer & service and a simplistic shell script. Gain command line access to your phone and become root. hosts.timer:

Tools for interacting with mce (Mode Control Entity). Provides the command line tool mcetool which allows to set and read various - well, modes on your phone. E.g.: disable lock screen animation: AFAICS it is not possible to get the status of only 1 control; you need to grep for it:

The phone will alert you that there's an update. Go to Settings => Sailfish OS Updates. As always, backup first. Download the update and choose to install it. Once again it complains that I don't have enough space on the root filesystem. This time I decide to bite the bullet and expand the root volume.

Recent versions of Sailfish OS (currently 4.4.0.58) use a socket that listens on port 22, and start sshd (to be precise, a per-connection sshd@.service) whenever someone knocks. Pretty neat, probably saves some resources when you don't need an ssh connection.

A.k.a "sailfish-browser". Its settings are not accessed from a pulldown but from the main app menu => Settings => Apps => Browser. There isn't much. Most notably: no (to me) acceptable search engine. But you can install the Search engines manager from OpenRepos.net, which allows you to search, add & remove search engines.

I was lucky to get a device that already comes with Sailfish OS 3 preinstalled. This is the most recent free version of Sailfish OS; I assume I will be able to upgrade it to Sailfish X (same version + Android support) if I want to. If you need to start from scratch (you will need a Jolla account), instructions are here.