It's an honorific, meaning "illustrious" or "enlightened general", and as such is not specific to Liu Bei.

For example, in the Records of the Three Kingdoms, Pei Song's annotations cite a passage where Huangfu Li (皇甫酈) addresses Li Jue (李傕) as 明將軍:

近董公之強，明將軍目所見...

 

In recent times, you yourself, illustrious general, saw with your own eyes how powerful Dong Zhuo was ...

It's an honorific, meaning "illustrious" or "enlightened general", and as such is not specific to Liu Bei.

For example, in the Records of the Three Kingdoms, Pei Song's annotations cite a passage where Huangfu Li (皇甫酈) addresses Li Jue (李傕) as 明將軍:

近董公之強，明將軍目所見...

In recent times, you yourself, illustrious general, saw with your own eyes how powerful Dong Zhuo was ...

It's an honorific, meaning "illustrious or enlightened general", and as such is not specific to Liu Bei.

For example, in the San guo zhi, Pei Song's annotations cite a passage where Huangfu Li (皇甫酈) addresses Li Jue (李傕) as 明將軍:

近董公之強，明將軍目所見. In recent times, you yourself, illustrious General, saw with your own eyes how powerful Dong Zhuo was ...

It's an honorific, meaning "illustrious" or "enlightened general", and as such is not specific to Liu Bei.

For example, in the Records of the Three Kingdoms, Pei Song's annotations cite a passage where Huangfu Li (皇甫酈) addresses Li Jue (李傕) as 明將軍:

近董公之強，明將軍目所見...

In recent times, you yourself, illustrious general, saw with your own eyes how powerful Dong Zhuo was ...