The Legionnaire-class courier vessel is a joint volus-turian corporate design (Jartus Shipping Inc., an ERCS-Elkoss joint-venture) that has been in service for the past 100 years, used by military interests (as a blockade runner) and civilian corporations alike. The design is prized for its low profile, low static build-up and fuel efficiency while also maintaining a high travelling speed. It's generally used to transport cargo loads to small for a large freighter on a delicate time-table through dangerous, less policed regions of space. Its often high-value and sometimes illegal cargo make it an appealing target for piracy and while overcoming its defenses is not a problem even for an haphazardly retrofit freighter, catching it first is the challenge.
However during the last decades its popularity has declined as new ship-classes have begun to supplement the Legionnaire niche, (e.g. the Sojourner-class (human, better core, better defensive package), or the Farseer-class (asari, passive stealth capabilities, better manouverabilty esp. in atmosphere). These have out-paced it by a fair margin. Many have been sold toward privateers in the Terminus Systems and Attican Traverse, and independent colonies, where they usually undergo retrofits in order to make them viable again, including less-than-legal variants where the cargo hold has been turned into a missile battery, the so-called privateer's special.
Cargo-Space: 100 C-Space standard pallets
Armaments: GARDIAN System (point-defense laser 8,62 sec cont. fire until overheat threshold, 4 packs of flares).
Speed: Very fast.
Range: Very far.
Shields: Yes, weak by modern standards, good at its inception.
MSV Iconoclasm (quarian retrofit)
Cargo-Space: 50 C-Space standard pallets (reduced due to specialised equipment and additional fuel cells)
Armaments: GARDIAN System (point-defense laser 12,3 sec cont. fire until overheat threshold, 4 packs of flares, 2 decoy drones). 2 side-mounted turrets (360°/180°, partially obstructed) with 2 4m mass accelerators each (116mm, 0,5 rps each)
Speed: very fast.
Range: very far.
Shields: above average for its type, compared to modern courier vessels.
The Iconoclasm is a ~40 year old pilgrimage gift that was heavily retrofit to serve as a retrieval vessel for the quarian patrol fleet, to return pilgrims and their gifts as well as the occasional unclaimed oddity the quarians came across. As such it has served the quarians well. After the 2nd Geth war it has been decommissioned after settlement on Rannoch and returned to the surviving family of those that brought the vessel to the fleet. See: Selin'Hylt.