A few "snippets" from Nokishita's latest tweets:
The specifications of RF400mm are 17 elements in 13 groups, minimum 2.5m, maximum 0.17 times, filter diameter insertion 52mm, φ163x367mm, 2.89kg.
Optically Identical to EF 400mm f/2.8L IS III USM lens. The latest EF version of the 400mm f/2.8L IS lens, introduced in late 2018, preserved the legendary sharpness of previous EF400mm f/2.8L lenses, but with a dramatic reduction in overall weight.
RF600mm is 17 elements in 13 groups, minimum 4.2m, maximum 0.15 times, filter diameter insertion 52mm, φ168x472mm, 3.09kg.
The specifications of the Canon RF100mm macro are 17 elements in 13 groups, minimum shooting distance 0.26m, maximum shooting magnification 1.4x, camera shake correction effect 5 steps (EOS R) / 8 steps (EOS R5), filter diameter 67mm, size. It seems to be φ81.5x148mm and weigh 730g.
Spherical Aberration (SA) Control Ring Allows Adjustments to Shape and Character of
Foreground/Background Bokeh
The RF100mm F2.8 L MACRO IS USM features Canon’s first adjustable Spherical Aberration (SA) control ring
on the lens barrel that allows you to adjust the depiction of the image’s background bokeh. Used to add a unique
emphasis to your imagery, the SA Control Ring allows the user to change the shape and character of the foreground
and background bokeh. A minus setting creates a dreamy, soft-focused look, while a Plus setting creates a
bubble-bokeh-type look.
...
The RF100mm F2.8 L MACRO IS USM is equipped with dual independent Nano USMs to help achieve
high-speed and focus accuracy throughout its focusing range.