diff --git a/unmaintained/bubble-chamber/bubble-chamber-docs.factor b/extra/bubble-chamber/bubble-chamber-docs.factor
similarity index 100%
rename from unmaintained/bubble-chamber/bubble-chamber-docs.factor
rename to extra/bubble-chamber/bubble-chamber-docs.factor
diff --git a/unmaintained/bubble-chamber/bubble-chamber.factor b/extra/bubble-chamber/bubble-chamber.factor
similarity index 100%
rename from unmaintained/bubble-chamber/bubble-chamber.factor
rename to extra/bubble-chamber/bubble-chamber.factor
diff --git a/unmaintained/bubble-chamber/common/common.factor b/extra/bubble-chamber/common/common.factor
similarity index 100%
rename from unmaintained/bubble-chamber/common/common.factor
rename to extra/bubble-chamber/common/common.factor
diff --git a/unmaintained/bubble-chamber/particle/axion/axion.factor b/extra/bubble-chamber/particle/axion/axion.factor
similarity index 100%
rename from unmaintained/bubble-chamber/particle/axion/axion.factor
rename to extra/bubble-chamber/particle/axion/axion.factor
diff --git a/unmaintained/bubble-chamber/particle/hadron/hadron.factor b/extra/bubble-chamber/particle/hadron/hadron.factor
similarity index 100%
rename from unmaintained/bubble-chamber/particle/hadron/hadron.factor
rename to extra/bubble-chamber/particle/hadron/hadron.factor
diff --git a/unmaintained/bubble-chamber/particle/muon/colors/colors.factor b/extra/bubble-chamber/particle/muon/colors/colors.factor
similarity index 100%
rename from unmaintained/bubble-chamber/particle/muon/colors/colors.factor
rename to extra/bubble-chamber/particle/muon/colors/colors.factor
diff --git a/unmaintained/bubble-chamber/particle/muon/muon.factor b/extra/bubble-chamber/particle/muon/muon.factor
similarity index 100%
rename from unmaintained/bubble-chamber/particle/muon/muon.factor
rename to extra/bubble-chamber/particle/muon/muon.factor
diff --git a/unmaintained/bubble-chamber/particle/particle.factor b/extra/bubble-chamber/particle/particle.factor
similarity index 100%
rename from unmaintained/bubble-chamber/particle/particle.factor
rename to extra/bubble-chamber/particle/particle.factor
diff --git a/unmaintained/bubble-chamber/particle/quark/quark.factor b/extra/bubble-chamber/particle/quark/quark.factor
similarity index 100%
rename from unmaintained/bubble-chamber/particle/quark/quark.factor
rename to extra/bubble-chamber/particle/quark/quark.factor
diff --git a/unmaintained/bubble-chamber/tags.txt b/extra/bubble-chamber/tags.txt
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rename from unmaintained/bubble-chamber/tags.txt
rename to extra/bubble-chamber/tags.txt