What does Reverse Button look like on Facebook?

On Facebook it is the design shipped in 16.0, shown above at full size. Older revisions are listed beneath it.

When did Facebook add Reverse Button?

Facebook first drew Reverse Button in 2.0, released February 20, 2017.

Meta Platforms, Inc. has shipped 12 versions of Reverse Button. Each is dated, so you can see when the design changed.

Facebook 2.0

Facebook shipped a new design for Reverse Button in 2.0, released February 20, 2017. The previous design is shown beside it.

The first Facebook release we hold for this emoji.

✳ marks a release that redrew this emoji. The rest re-shipped the design unchanged.

What does Reverse Button look like on Facebook?: On Facebook it is the design shipped in 16.0, shown above at full size. Older revisions are listed beneath it.
When did Facebook add Reverse Button?: Facebook first drew Reverse Button in 2.0, released February 20, 2017.
How many times has Facebook redrawn Reverse Button?: Meta Platforms, Inc. has shipped 12 versions of Reverse Button. Each is dated, so you can see when the design changed.