You don't need this information... ToA clearly states enough lore about Ubtao that you can guess safely what his portfolio is, or apply the domain you think fits best. There is no need for google, you can use your copy of the Player's Handbook to pick a domain easily.
"This contains everything you need!"
"My player wants to play this so I need this information..."
"Nah. I am going to assert my opinion on you. I am going to tell you you do not need this information!"
What ToA states about Ubtao is vague at best. If inference is needed that is clearly not "clearly stating". If you need to guess that is literally the opposite of "clearing stating". If you need external sources to make use of the information that is clearly not having everything you need. There is great disconnect.
Considering by googling Ubtao it's just going to tell you what his portfolios are in previous editions, you'll have to guess which 5E ones to pick for him anyway, so it's not that helpful.
Going off previous editions is actually helpful. It actually gives comparisons to map relevant domains.
The 3e FRCS gives you Planning, Plant, Protection, Scalykind as domains for Ubtao.
The 2e Powers and Pantheons gives creation, the labyrinth of life, jungles, the Jungles of Chult, the Tabaxi, dinosaurs for his portfolio.
Oh. What is that. 5e has the Protection the Life and the Nature domains. Oh. What it is that? I did not need to guess? That is helpful. Great.
The 3e FRCS gives you his alignment. N. Which is not clearly stated in ToA.
If your ability to create your own adventure is broken by missing a god's portfolio (I assure you I need no such thing), then you may be googling for more help regardless of what setting book you buy.
Whatever helps you feel better.