Trying to find a source segment of a formula

I'm trying to dissect the following formula to better understand. Where can I find the information for s and t please? Its not in name manager.

=LET(t,ALL!$K:$K,s,SEQUENCE(ROWS(t)),MAX(FREQUENCY(IF(t="W",s),IF(t<>"W",s))))

Thanks.

=LET(t,ALL!$K:$K,s,SEQUENCE(ROWS(t)),MAX(FREQUENCY(IF(t="W",s),IF(t<>"W",s))))

T is defined by the bit in red and s by the bit in blue.

If you think of =LET() as being a bucket, it's easier to understand. It doesn't of itself, actually do ANYTHING.

LET will keep various sub-formulae for convenient (multiple) re-use in the main formula. In your case, there are to subformulae, t & s. Instead of calculating them every time (which then gets slow) they are calculated once and each of them is used twice in the final formula. =LET() enable more complex functions to be calculated with greater efficiency.

Finally, in these longer and longer formulae, I tend to put all the bits of the raw data that I need IMMEDIATELY after LET... to make it easier to adjust ranges, if needed. They're all there (and only there) at the start of the formula.

In my words, the start of a LET clause sets various parameters that you go on to use in a formula.

So, for example, consider this:

=IF(COUNTIF(A:A,"Marvo")>1,"Happy Days",COUNTIF(A:A,"Marvo"))

which could be condensed to:

=LET(c,COUNTIF(A:A,"Marvo"),hd,"Happy Days",IF(c>1,hd,c))

You can give your parameters (almost) any name you like.