The feature that displays a bar indicating the amount of reduced HP when a unit's HP is reduced has been updated to the latest version published by Zane. It is based on the high contrast version for accessibility, with some modifications.

Now subdivided into 11 levels (10 levels in effect)
Previously, my hack used an older version of the HP bar that showed 5 levels; Zane's latest version shows 13 levels. The 13 levels of the bar are achieved by using the full 16 dots of the unit's drawing area, but since using the full width would cause the HP bars to stick together with the bars of adjacent units, I trimmed off one dot on each side, so there are now 11 levels.
The HP bar is also 14 dots in GBA FE hacks, so if you have an experience playing them, you will be able to accept this without any discomfort.
Changed the color when HP is half or less
The bar has been changed to turn yellow when HP is half or less. In my hack, the HP display on the stats screen turns red when the HP is half or less, so I changed the bar to match that specification. If the bar is red, it will be buried and overlooked on the map, so I made it bright yellow.
Also, due to the way the palette is used, I changed the HP bars of all units to be hidden during map combat. They will reappear when the combat is over, so you probably won't find it inconvenient to play. This change may also improve (during a map combat) the missing sprites caused by the large number of units lined up side by side in Chapter 16A, etc.
Acknowledgements
This feature is based on "HP bars" code published by Zane Avernathy on GitHub. Thank you very much.