You're probably aware of this, but the current naming scheme doesn't allow showing multiple visits that happened on the same day, which does happen sometimes.
For example:
$ ls <mountpoint>/origin/https%3A%2F%2Fgithub.com%2Fwangnuannuan%2Fembarc_applications 2018-10-12 2018-10-15 2018-10-16 2019-03-08 2019-06-27 2020-03-27
softwareheritage=> select visit, date from origin_visit, origin where origin=origin.id and origin.url='https://github.com/wangnuannuan/embarc_applications';
visit | date
-------+-------------------------------
1 | 2018-10-12 00:24:31.590759+00
2 | 2018-10-15 07:48:28.233645+00
3 | 2018-10-15 13:52:08.767357+00
4 | 2018-10-15 17:22:29.282168+00
5 | 2018-10-16 09:04:30.053555+00
6 | 2019-03-08 20:08:27.763904+00
7 | 2019-06-27 12:55:15.211531+00
8 | 2020-03-27 01:03:17.956588+00