On 2016-12-15 21:06, Drew Adams wrote:
>> Thus, without making things harder for many other facilities.
> No one has given an example of how narrowing makes things
> hard "for many other facilities" - or even for one facility.

I think I gave one example of how narrowing breaks proof-general; in fact, I explained I developed my own alternative to narrowing with overlays because other packages broke in the face of regular narrowing.