Source: mate-indicator-applet Version: 1.20.0-1 Severity: serious mate-indicator-applet was removed from buster when ido was removed due to #895039.
The changelog says: mate-indicator-applet (1.18.1-2) unstable; urgency=medium ... * debian/control: + Alternatively B-D on libido3-0.1-dev (>= 13.10) or libayatana-ido3-0.4-dev. Alternatively B-D on libindicator3-dev (>= 16.10) or libayatana-indicator3-dev. This lets this package build against Ubuntu Indicators in Ubuntu and derivatives, while in Debian and derivatives (except Ubuntu) the new Ayatana Indicators implementation gets used. ... -- Mike Gabriel <sunwea...@debian.org> Mon, 04 Dec 2017 15:29:57 +0100 But the build dependencies are actually: Build-Depends: debhelper (>= 11~), dpkg-dev (>= 1.16.1.1), intltool, libgtk-3-dev, libido3-0.1-dev, libayatana-ido3-0.4-dev, libindicator3-dev, libayatana-indicator3-dev, ... This is not an alternative build dependency, and makes the build dependencies not fulfillable without ido.