for example, col LIKE 'foo%' or col ~ '^foo', but not col LIKE '%bar', which would require a reversed index on the field. Postgres will automatically use the reverse index for LIKE '%bar'
Or if it doesn't:
It doesn't, otherwise the documentation wouldn't need to point out: but not col LIKE '%bar' ...
for example, col LIKE 'foo%' or col ~ '^foo', but not col LIKE '%bar', which would require a reversed index on the field. To use the reversed index, query with reverse(col) like reverse('%bar').
This type of commentary isn't usually something we include in the documentation...and I'm not too keen on "reversed index" as a phrase regardless.