Happy New Year and good afternoon,
Since some l3kernel update in December I am getting kernel/invalid
-variant warnings, as in
* LaTeX warning: "kernel/invalid-variant"
*
* Variant form 'cF' invalid for base form '\tl_if_blank:nF'.
It is issued for the line of code
\cs_generate_variant:Nn\tl_if_blank:nF{cF}
that used to work without warning before. Which is the correct method for
generating variants of conditionals?
Alexander