Corresponding source for @ffmpeg/core 0.12.10

Echoryte written offer

For at least three years from the last distribution of the corresponding
object code, Echoryte offers any third party a complete machine-readable
copy of the Corresponding Source, including the scripts used to control
compilation and installation. Request it through the deployment's /contact
page. Any charge will not exceed the distributor's actual cost of the physical
medium and postage. The upstream tag below is an immediate convenience copy;
this written offer does not depend on that external URL remaining available.

Upstream repository:
https://github.com/ffmpegwasm/ffmpeg.wasm

Exact release tag:
https://github.com/ffmpegwasm/ffmpeg.wasm/tree/v0.12.10

Expected tag commit:
c3a763857c5e615ae8674715ad5e4f63ff469e9d

Obtain the complete source, including the pinned FFmpeg submodule and build
scripts, at no charge with:

git clone --branch v0.12.10 --depth 1 --recurse-submodules \
  https://github.com/ffmpegwasm/ffmpeg.wasm.git ffmpeg.wasm-0.12.10
cd ffmpeg.wasm-0.12.10
git rev-parse HEAD

The final command must print the expected commit above. Build documentation is
in the checked-out repository under docs/docs/contribution/core.md and the
build/ directory. This application distributes the single-thread UMD build
from packages/core/dist/umd without local modification.

The source tag and this written retrieval information correspond to the exact
object code version distributed by this application. Keep this notice,
COPYING.GPLv2, and manifest.json available for as long as that object code is
offered for download.