As of version 1.13.0, it's python2-only.
Apache Subversion 1.14 will introduce support for Python 3: http://subversion.apache.org/docs/release-notes/1.14
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=65603892d09269e6d48435269f26aeb3868083c0 commit 65603892d09269e6d48435269f26aeb3868083c0 Author: Andreas K. Hüttel <dilfridge@gentoo.org> AuthorDate: 2020-05-18 22:11:01 +0000 Commit: Andreas K. Hüttel <dilfridge@gentoo.org> CommitDate: 2020-05-18 22:14:50 +0000 dev-vcs/subversion: Add prerelease for testing (no keywords) Bug: https://bugs.gentoo.org/686148 Bug: https://bugs.gentoo.org/706136 Bug: https://bugs.gentoo.org/223747 Bug: https://bugs.gentoo.org/712042 Package-Manager: Portage-2.3.99, Repoman-2.3.22 Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org> dev-vcs/subversion/Manifest | 1 + dev-vcs/subversion/subversion-1.14.0_rc2.ebuild | 537 ++++++++++++++++++++++++ 2 files changed, 538 insertions(+)
1.14.0 now has py3.