Text in Hebrew and Arabic renders correctly — it is reordered and shaped when the line is laid out. What is missing is the effect of writing-mode and direction on the boxes themselves:
writing-mode: vertical-rl / vertical-lr do not change the axis a block flows along.direction: rtl does not flip the inline direction, so a flex row still starts at the left, and an absolutely positioned box with left: auto; right: auto still lands at the left edge.
This is what "supports RTL" would mean at the layout level rather than the text level.
Text in Hebrew and Arabic renders correctly — it is reordered and shaped when the line is laid out. What is missing is the effect of
writing-modeanddirectionon the boxes themselves:writing-mode: vertical-rl/vertical-lrdo not change the axis a block flows along.direction: rtldoes not flip the inline direction, so a flex row still starts at the left, and an absolutely positioned box withleft: auto; right: autostill lands at the left edge.This is what "supports RTL" would mean at the layout level rather than the text level.