There were some speculation/rumours started a few years ago that the J-35 would have a ventral weapons bay that was near identical in dimensions to that of J-20. It was accompanied by some speculative comparisons at the time, like this one below
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Certainly based on the pictures of J-35, it is very much within reason that its weapons bay may have similar or even identical dimensions to that of J-20 -- it's very believable in terms of length and width, and potentially depth as well.
It also makes a fair bit of sense in terms of integration/footprint -- it would mean that weapons developed for the IWB of one of the two aircraft would also be physically/dimensionally compatible with the other.
Important for A2A weapons of course, but also important for A2G weapons given both J-20 and J-35 will have some powered A2G and standoff weapons developed for internal carriage