I'm able to search for https://developer.garmin.com/downloads/connect-iq/eclipse in Eclipse Mars. I can even click through everything. But after I click finish, I get the following error:
An error occurred while collecting items to be installed
session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
Artifact not found: developer.garmin.com/.../IQ_AppSettingsEditor_3.2.2.jar.
developer.garmin.com/.../IQ_AppSettingsEditor_3.2.2.jar
Artifact not found: developer.garmin.com/.../IQ_IDE_3.2.2.jar.
developer.garmin.com/.../IQ_IDE_3.2.2.jar
Artifact not found: developer.garmin.com/.../IQ_PackageWizard_3.2.2.jar.
developer.garmin.com/.../IQ_PackageWizard_3.2.2.jar
Artifact not found: developer.garmin.com/.../IQ_SdkManager_3.2.2.jar.
https://developer.garmin.com/downloads/connect-iq/eclipse/plugins/IQ_SdkManager_3.2.2.jar