Depending on your input a mistyped address in the address bar of Firefox may start a web search. This is the default behaviour of Firefox, but I do not like that very much. So I was searching for a solution and found one at Reddit:
How to completely disable search in the address bar?
There are two parameters to be set to `false` in `about:config` of Firefox:
The first setting is to suppress the web search. The second setting is to keep Firefox from trying to turn your input into a web address by adding a suffix (`.com`).
To have an additional search bar go to "Settings" > "Search" and select "Add search bar in toolbar".
Now you can press Ctrl-L to focus the address bar and press Ctrl-K to focus the search bar.