{nei} and {no'a} in a {sei} bridi

[guskant]

I repost to beginners' list my question that I put in the lojban list:
https://groups.google.com/d/msg/lojban/1jw3fYM6JNI/tnMsp9n2YvsJ

Is a {sei} bridi in a bridi called an embedded bridi? For example,

1) ko'a ko'e sei nei brode se'u broda
2) ko'a ko'e sei no'a brode se'u broda
In which sentence is {broda} repeated; or none of them?

On the other hand, I think a {to} sentence in a bridi is neither an embedded sentence nor a part of the bridi in this context. For example,
3) ko'a ko'e to nei brode toi broda
4) ko'a ko'e to no'a brode toi broda
in neither 3) nor 4), {broda} is repeated; or am I wrong?

A {sei} bridi is grammatically a free modifier just like a {to} sentence, but semantically a metalinguistic bridi, which is somehow similar in meaning to {BAI lonu} bridi, which is clearly an embedded bridi, in which {no'a} works. I am curious to know if {nei} ji {no'a} in a {sei} bridi repeats the main bridi.