This mod has two main functions: Browsing the global namespace, and running scripts. Even if you only use it for the first, it's still well worth it.
Browsing the global namespace has a lot of useful functions: It's a great way to learn about the environment of Minetest with its data tables of registered items, constants, and also every API, documented or undocumented (mostly the former). Likewise with mods' APIs and data tables that are in the global namespace. Sometimes you spot a global that's not meant to be there and can go fix it - though other tools like Luacheck are meant to help with problems like that as well. Other times you want to look through and check what's registered in terms of ABMs, schematics, entities and so on.
Although the presentation is not as ideal as a specialised view for developers or as easy to read as an Wuzzy's doc mod, you know you're getting the actual data when you view it through the QA Block and can refer to it in your code. You can't find everything with the QA Block of course - a lot of mods have local variables embedded in their code that can't be accessed from outside the mod. But QA block inspects the overall system and global namespace comprehensively.
The more advanced function is to use the checks that are built into the mod, as well as writing your own. A good number of scripts are built in to help you find problems, hence the name QA for "Quality Assurance", since those are the kinds of checks that QA testers regularly need to perform. You can find broken recipes, list entities, find redundant-looking items. Some of the QA scripts generate external files such as a graphviz format recipe graph; you could use QA scripts to make your own reports or even prepare data for external programs.
You can write your own QA scripts and add them to the QA block directory. I don't always recommend modifying code, but there's no reason you can't make light fork of the mod to add your own QA scripts. I've found QA scripts helpful for developing mods, such as finding out if a specific data structure is in place that should be there. Running QA scripts isn't a replacement for automated tests with something like mineunit, but it's very helpful when iterating and debugging.
This mod has two main functions: Browsing the global namespace, and running scripts. Even if you only use it for the first, it's still well worth it.
Browsing the global namespace has a lot of useful functions: It's a great way to learn about the environment of Minetest with its data tables of registered items, constants, and also every API, documented or undocumented (mostly the former). Likewise with mods' APIs and data tables that are in the global namespace. Sometimes you spot a global that's not meant to be there and can go fix it - though other tools like Luacheck are meant to help with problems like that as well. Other times you want to look through and check what's registered in terms of ABMs, schematics, entities and so on.
Although the presentation is not as ideal as a specialised view for developers or as easy to read as an Wuzzy's doc mod, you know you're getting the actual data when you view it through the QA Block and can refer to it in your code. You can't find everything with the QA Block of course - a lot of mods have local variables embedded in their code that can't be accessed from outside the mod. But QA block inspects the overall system and global namespace comprehensively.
Review concludes in a comment
The more advanced function is to use the checks that are built into the mod, as well as writing your own. A good number of scripts are built in to help you find problems, hence the name QA for "Quality Assurance", since those are the kinds of checks that QA testers regularly need to perform. You can find broken recipes, list entities, find redundant-looking items. Some of the QA scripts generate external files such as a graphviz format recipe graph; you could use QA scripts to make your own reports or even prepare data for external programs.
You can write your own QA scripts and add them to the QA block directory. I don't always recommend modifying code, but there's no reason you can't make light fork of the mod to add your own QA scripts. I've found QA scripts helpful for developing mods, such as finding out if a specific data structure is in place that should be there. Running QA scripts isn't a replacement for automated tests with something like mineunit, but it's very helpful when iterating and debugging.