Labeling the frames

I am curious to whether Toonboom Harmony Essentials has the option to label your drawings as keyframes, inbetweens, and breakdowns (i.e. the red ‘K’ or blue ‘B’ in the cell in the X-Sheet) . I am unable to find the option in the interface.

No, it doesn’t. It doesn’t have anything considered ‘advanced’, and I suppose that - besides textured lines, vector textures brushes, shift and trace tool, advanced onion skin, pencil lines with variable width, repaint and protect colour, etc. - is considered advanced. There are no Flipping and Mark Drawing toolbars in Essentials.