Meshtastic

It's definitely proprietary at the physical layer. You cannot make your own LoRa RF chips. It's patented, closed-source, and owned by Semtech. There is no public specification.

However, the higher layers above physical are open and the proprietary radio chips are well-supported and widely available to hobbyists. There's not much else in the low-power, low-cost, and no-license required to transmit niche, and it works really well at what it aims to do.

Yes:

https://www.semtech.com/lora/what-is-lora

What Is LoRa®?

LoRa (short for long range) is a spread spectrum modulation technique derived from chirp spread spectrum (CSS) technology. Semtech’s LoRa is a long range, low power wireless platform that has become the de facto wireless platform of Internet of Things (IoT). LoRa devices and networks such as the LoRaWAN® enable smart IoT applications that solve some of the biggest challenges facing our planet: energy management, natural resource reduction, pollution control, infrastructure efficiency, and disaster prevention. Semtech’s LoRa devices have amassed several hundred known uses cases for smart cities, homes and buildings, communities, metering, supply chain and logistics, agriculture, and more. With hundreds of millions of devices connected to networks in more than 100 countries and growing, LoRa is creating a smarter planet.

However, LoRa uses unlicensed subgigahertz radio spectrum and the LoRaWAN standard is driven by the non-profit LoRa Alliance, which operates in a similar capacity to the Wi-Fi Alliance.

https://lora-alliance.org/lorawan-for-developers/

LoRaWAN® Standards Documents

The LoRaWAN® standards documents are developed and maintained by the LoRa Alliance®: an open association of collaborating members. To fully define the LoRaWAN® standards, and to ensure interoperability among devices and networks, the LoRa Alliance® develops and maintains the following documents:

Link Layer standard

Back-End Interfaces standard

Firmware Update Over-the-Air standard

Regional Parameters

Certification Program

While these standards define the technical implementation, they do not define any commercial model or type of deployment (public, shared, private, enterprise) and so offer the industry the freedom to innovate and differentiate in how a LoRaWAN® system is implemented.

The standard defines the end-to-end architecture and so provides seamless interoperability between manufacturers, as demonstrated via the device certification program.

If I understand correctly, this means technically only the physical layer of the network is proprietary technology, and link-layer upward are open. So technically proprietary but for all intents and purposes generally open?