snap install MQTTX_1.6.2_amd64.snap
安装提示
error: cannot find signatures with metadata for snap "MQTTX_1.6.2_amd64.snap"
但我在第三方平台中只能下.snap包,没有.assert文件.

查阅文档发现

If you don't care about the assertion, you can run snap install --dangerous <the darktable snap you downloaded>, but then you won't receive updates.

可以用 --dangerous参数忽略.
snap install --dangerous MQTTX_1.6.2_amd64.snap