In addition to the existing `exports` conditional exports we ship
as part of APF v13, we want to expose the non-bundled ESM2020 output
through the `esm2020` conditional name. Additionally we will expose
the flat ES2020 files through the `es2020` conditional field, allowing
consumers (like the CLI) to prioritize certain formats.
e.g. consider the case with RXJS where it currently defaults to
the ESM5 output. The CLI could now set `es2015` as the conditional
to leverage the ES2015 output of RXJS. This unveils a problem though
since this would also mean that `ES2015` output of the framework Angular
packages would be used instead of the available ES2020 output. Here is
the additional `es2020` conditional helpful as it allows the CLI to
prioritize `es2020`, fallback to `es2015` and lastly fallback to `default`.
if none do match for a certain package.
PR Close#43740
Paul Gschwendtner