See https://archive-media.formlabs.com/upload/XL-DataSheet.pdf section titled FLTOTL05.
And here’s an older version of the material properties graphic which still included it: Engineering Materials at a Glance
Also https://support.formlabs.com/s/article/Using-Tough-Resin-V5 although it doesn’t have as much there.
I agree it’s a unique color. If they do ditch it, you may have some luck pigmenting Clear or Durable (of course it wouldn’t have the same properties).