In two minutes
It’s a ZIP. Rename any .ora to .zip and look inside: a mimetype file, a stack.xml listing the layers top to bottom, one PNG per layer, a flattened mergedimage.png, and a thumbnail.
It’s open. The spec was proposed at the first Libre Graphics Meeting in 2006 as an alternative to PSD, and nobody owns it. That’s why the free editors agreed on it as the way to hand layered work to each other.
It’s pixels only. Names, order, opacity, visibility, position and blend mode travel. Text, shapes and masks don’t — every app writes them as paint.
Questions
How do I open a .ora file?
Drop it on this page to see its layers without installing anything, or open it in Krita, GIMP, MyPaint or Image Horse.
How do I convert a .ora file?
Open it above and press PNG for a flattened image, or PSD for a layered Photoshop file. Both are made in your browser. There are dedicated pages for .ora to PNG and .ora to PSD.
Is .ora a Krita file?
Krita reads and writes it, but .ora is not Krita's own format — that's .kra. OpenRaster is the shared one any editor can open.