The map you were just viewing is a simplified map interface that I wrote for use on my flip phone, which uses an old browser that doesn't understand modern Javascript. It uses map tiles from OpenStreetMap, which is a crowdsourced map data project. Searches are performed using Nominatum.
I've set up keybindings so that 2, 4, 6, and 8 will pan north, west, east, and south, and 3 and 9 will zoom in and out, respectively. (Remember to switch to numeric input. You may also need to focus into the page.) With a regular keyboard, the arrow keys and plus/minus will behave as expected.
You can also just focus a button and activate it using the keyboard if your user agent doesn't produce the right kind of keyboard events.
If your phone doesn't let you type directly into the page, click the "#" button. You can then type keybindings (2, 3, 4, etc.) into a hidden text field and those keypresses will be captured correctly. When you want to exit this mode, you may need to use set/enter/done to exit the hidden text field.
Press the "M" button to show/hide additional options: