What's the meaning of 登假 in old daoist scriptures like Zhuang Zi? In the old daoist text Zhuang Zi, we see 登假 at least twice in the Inner Chapters (5.1 and 6.2).

In the first part, it gives the meaning of departure and "going up" (to isolation in the mountains? To the heavens above?). In the second part, it gives the meaning of ascension, of reaching a higher goal (grasp the Dao).

I also saw some references to the death of an emperor or king.

I know 登 means ascend, climb, but 假 means fake, suppose or vacation. What's the contribution of 假 to the meaning observed in the Zhuang Zi translations, or even to the death of a king?
《康熙字典》
又《集韻》《正韻》與格同，至也。《易·萃卦》王假有廟。


from Kangxi Dicitionary: the 13th meaning of 假

It pronounces as 格, means 'arrive'. Example sentence from Yi Cuigua: The King arrives at the ancestral temple.

^ref