Keyboard Shortcuts is a great new addition to Joomla 4.2.

The Shortcuts are a productivity feature many will find useful, plus a few hidden gems.

Keyboard Shortcuts

The keyboard shortcuts began life as a Google Summer of Code (GSoC) project. Kumar Shivam - AccessibilityProject.
It is a system plugin that is enabled by default.

It introduces keyboard shortcuts to the administrator area.

The best way to start to get to know keyboard shortcuts is to log in to the administrator area of your Joomla 4.2 site and then press J and then X. A modal window will pop up with all of the shortcuts showing.
Do note that it's not pressing two keys at the same time, it is one followed by another and you have a 2-second window to make the key presses. This is configured in the system plugin where the only configuration is the timeout which is in milliseconds.

J A  is the configuration for Save. 

J S is Save and Close.

J Q Will Cancel whatever you are editing and take you to the list view.

J N New will create a new article or menu.

J F Will take your cursor to the Search area on any page that has one

J O Opens the options if you are on a page that has options

J H are the keyboard shortcuts to bring up any Help page window

J M Toggles the “Toggle Menu” changing the space you have on the page

J X brings up an Overview of the keystrokes

J D takes you to the Home Dashboard

There is a onLoadShortcuts event which can be used to extend the shortcuts.
The current plugin is just the start. There are plans to allow the editing of shortcuts, the possibility to disable them, and changing the overview-text hint to a button in the corner for starters.
3rd party plugins
3rd party plugins need to provide an array of shortcuts which are objects:

• shortcut: string
• selector: string
• title: string

The shortcut needs to be a keyboard input, separated by a plus e.g. "J + Y" or "ALT + Z + 7" (currently there is really no filtering).
Selectors are similar to CSS selectors to target an element. When it is an input element, the shortcut gives focus, otherwise, it will be clicked.
The title will be displayed in the overview. It could be the name of the target.

I have really enjoyed using both of these two new features. The Multi-factor authentication feels so much better since Joomla 4.2 It feels a well-thought-out package which has the strength of the plugin system to be future-proofed with new authentication plugins being possible to fit into this great system.

Keyboard Shortcuts need the muscle memory to embed a little more but I am regularly using the save, save and close and the J X overview. The J A (save) has already saved me from losing articles and changes.

Thanks to Nicholas K. Dionysopoulos and Franciska Perisa for doing all the hard work in this article, and supplying the much-needed facts.

Other features

There are other features hidden away in Joomla 4.2
Some that caught my eye are listed below.

User-defined hide table columns

Decide for yourself which columns to display for any table. The button shows an updating count of how many columns are shown.
The choice of which column to display is stored in local storage so it is persistent for you in your browser for that site.

Indicate if the category is not published

Until Joomla 4.2 Articles that are in a category which is unpublished or trashed are not visible on the site but there is no way you can tell this from the article manager
Now in Joomla 4.2 there is an indicator if the category is unpublished or trashed and the published icon changes to a disabled icon and adds a tooltip to the icon.

Allow disabling session metadata tracking for guest users

Improve performance for sites that do not use User registration/login features.
There is already an option to disable "Track Session Metadata",

However, it is more useful to be able to disable it only for non-registered users, while keeping track of metadata for logged-in users.

Smart Search: Allow fuzzy word matching

A regular request was to be able to find compound words. Smart Search until now matched the words exactly, even though it uses a stemmer to find common roots for a word. However, those stemmers can only work on single words and "fail" on compound words. Now Joomla 4.2 allows switching the matching method between exact matches, matching words starting with the given term and matching words which just contain the term in a random position.