It's just CLI in web browser window. Offers nothing more than you can already do in normal CLI. There are lots of better alternatives (e.g. sqlitebrowser).

Excellent add-on for not only fiddeling around with Firefox and Thunderbird sql db's but also useful for debugging or creating data when using sqlite in my own simple java or python programs to store data

Excellent! Used it to browse firefox sqlite files for deleted history, learned a lot about sqlite in the process. A serious developer tool.

Maybe not the full experience of a dedicated program but it does the job and it very useful for quickly see some database data

i don't know how to create table and new database

Just what I was looking for. Write commands and see the output.