Someone has hit the 10MiB limit (and of course it's the number of
javascript packages), and we don't handle it fantastically currently.
And even though you can't pass a variable of that size in one go, it's
plausible that someone might do it in multiple passes.
See #5267.
We were flip-flopping between the two terms, so we now use one. We
still mention "array" in the chapter, and it's still `read --array`,
though.
Fixes#5846.
[ci skip]
