Lacunari's default license is the GNU Affero General Public License v3.0. Use it, run it, modify it, self-host it: all free, all forever. The AGPL adds one clause the plain GPL does not have, and it is the clause that matters here: if you distribute the software, or run a modified version of it as a network service for other people, you have to release your source under the same terms. Running an internal fork on your own servers, for your own team, triggers nothing. Offering that fork to other people over a network does.
That clause is also exactly why some organisations cannot use AGPL software at all, whatever they think of the project. A team building Lacunari into a proprietary product, or standing up a hosted version of it without publishing their changes, cannot do either under AGPL terms. For them, a commercial license is available: hello@lacunari.com.
The CLA is what makes both possible at once
A project cannot dual-license code it does not fully hold the rights to, and once more than one person has contributed, no single copy of the license text can bind all their combined copyrights. Lacunari's CLA is what closes that gap. Contributing means granting Evan King a copyright license broad enough to relicense the combined work, including under proprietary commercial terms. The CLA is explicit about why: "Without this sentence the project cannot offer commercial licences, and the dual-licensing model does not work."
The CLA is a license, not a copyright transfer. Contributors keep the copyright to their own contribution and can reuse it anywhere else, for anything, forever. What they grant is permission for that contribution to travel inside Lacunari under both license tracks, alongside everyone else's.
What this means if you're evaluating it
Happy to self-host, comfortable publishing any changes you make and any service you build on top: AGPL costs you nothing and asks nothing further of you. Need to embed it in something you sell without shipping your source, or run it as a hosted product without releasing your modifications: that is what the commercial license exists for, and it exists specifically so that path does not require going around the license or hoping nobody checks.