Forking this form  Issue 736215  comment #24 and adding some extra thoughts I had recently on the topic

Problem
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I see the practical need for TBR but there are two general problems:

1) It's not immediate for reviewers getting TBR'd to figure out what are they TBR'd for. Not every author is nice enough to write "TBR foo@ for content/browser/bar.cc". And even when they do, it's quite hard to scrape these in CLs that have too many comments.

2) TBR completely bypasses owners check, even when the author doesn't mean it.
Concrete example: in [1] I'm TBR-ing two people because I am doing silly mechanical changes in chrome/browser/metrics/* and net/url_request/url_request_quic_perftest.cc.
The rest of the CL is not mechanical though and I don't want to accidentally bypass the actual reviewers. For instance in that CL I am touching a mojom file that requires a SECURITY_OWNER stamp. I really don't want to accidentally skip that.

Proposal
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Rework the TBR format to be very explicit. For instance in that CL I would have loved to:
TBR[content/browser/metrics/*] = asvitkine
TBR[net/url_request/url_request_quic_perftest.cc] = xunjieli

And leaving the possibility to do 
TBR[*] = foo
In cases of urgent things (e.g. reverts) 

And, of course, TBR[*] should be extremely socially unacceptable for anything other than reverts.

[1] https://chromium-review.googlesource.com/c/544976/