s3se is based on Jonha's String Translate, which he allowed us to take over development of. Many thanks to him for his original design and code.
Contrary to its original name, it does not have any translation capabilities. What it does best is allow the user to add and delete strings and STBLs, merge and import STBLs, and selectively or all at once copy the strings from one language to the others.
About strings and STBLs background reading and terminology
The s3se Main Form which button does what
The s3se Menus which option does what