The command \environment is used for including style setups
This includes the style setups defined in the file argument. Usually used in combination with Project structure, but it could be used in any input file.
The environment file:
% env_packed_items.tex \setupitemize[packed]
A file that uses that environment:
% myfile.tex \environment env_packed_items \starttext bla bla \startitemize \item \stopitemize \stoptext