Eg in julia --help, and also the manual. At least that the flag exists and sets the project, the concept of the project is (will be?) explained in the relevant section of the manual (maybe cross-reference).
cf 955a950342ebba88d05aa1b82553500a283ecb60, #27816
Manual doc added in https://github.com/JuliaLang/julia/pull/28556
I think that #28556 primarily documents JULIA_PROJECT, and mentions --project in passing. Documenting --project in --help and the manual would still be useful.
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I think that #28556 primarily documents
JULIA_PROJECT, and mentions--projectin passing. Documenting--projectin--helpand the manual would still be useful.