I created a 16-bpp RGB file in Display P3 in photoshop, filled it
with (0, 255, 0), and then drew something on it with (100, 255, 0).
(Since it's a 16-bpp image, 255 ix stored as 0xffff and 100 is stored
as 65535 * 100 / 255 == 0x6464 in the file.)
I verified that Edit->Convert to Profile...->sRGB resulted in an
image filled with (0, 255, 0) in that color space (due to gamut
clipping).
Similar to these:
* https://webkit.org/blog-files/color-gamut/Webkit-logo-P3.png
* https://www.dropbox.com/s/tgarynpj65ouafd/insta-logo.png?dl=1
...but in green instead of in red, and hand-drawn by me so no license
concerns.
