Boost Parameters - What's It Called?

There is no single thing from Boost that I have a need for in every project, but I nearly always use something. Some of these are obsolete with the addition of ranges. Specialized containers like flat maps, static vector, and stable vector. Boost lexical cast because parsing arbitrary numeric types in C++ is still absurdly difficult. Although from now on, they will only be using FMT or std format and boost hash. They continue.