According to the changelog (https://github.com/greatscottgadgets/ubertooth/releases) python3 supported has been added in this version.
Could you please test and revise the ebuild?
Only USE=specan requires python, which is about to be removed.
The bug has been referenced in the following commit(s):
Author: Andreas Sturmlechner <firstname.lastname@example.org>
AuthorDate: 2018-06-26 21:12:15 +0000
Commit: Andreas Sturmlechner <email@example.com>
CommitDate: 2018-06-27 19:00:21 +0000
net-wireless/ubertooth: Drop USE=specan, depends on Qt4
Package-Manager: Portage-2.3.40, Repoman-2.3.9
.../ubertooth/ubertooth-2017.03.2-r1.ebuild | 70 ++++++++++++++++++++++
net-wireless/ubertooth/ubertooth-9999.ebuild | 42 ++-----------
2 files changed, 75 insertions(+), 37 deletions(-)
Last version to require py2 dropped in commit 38be64e6.