Ask HN: Can you help me find a popular open-source tool?

Hello HN. A while ago I came across a post here that showcased a really neat FOSS project which I am very certain was made and open sourced by the uk government.

It a was a web based app that included a very extensive collection of data tools such as data converters (i.e. json->csv), currency converters, hashing data and back and all sorts of other types of tools like that... it was very similar to 123apps.com but also leagues ahead of it.

I can't for the life of me remember what it was called and searching for it hasn't yielded anything useful. All I associate with it is the gov.uk website and their github page... But the problem is I couldn't find it on there either, so it could very well be a false association but I am not entirely sure.

I know this is an extremely long shot given how little I remember about the project, so I really appreciate anyone who tries to help me find it.

Thank you.