The last few messages in pgsql-committers show links like
Details-------https://git.postgresql.org/pg/commitdiff/643428c54b95d472c6d949c3c3c11f347e371a2b
which yields a 404. The correct link seems to be
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=643428c54b95d472c6d949c3c3c11f347e371a2b
Not sure what changed ...
regards, tom lane