With toes broken Heather goes after some arcane matters (9)
I believe the answer is:
esoterica
'with toes broken heather goes after some arcane matters' is the definition.
I can't tell whether this definition defines the answer.
'with toes broken heather' is the wordplay.
'with' indicates putting letters inside.
'broken' indicates anagramming the letters.
'heather' becomes 'erica' (the plant genus Erica includes heather plants).
'toes' anagrammed gives 'sote'.
'sote' inserted inside 'erica' is 'ESOTERICA'.
Can you help me to learn more?
(Other definitions for esoterica that I've seen before include "Mysterious or secret things" , "Highly-specialised subjects" , "Specialized publications" , "Secret subjects" , "Coarse tie? (anag)" .)