These map to the same thing as HTML ins/del.

Here's the relevant commit to the ARIA spec:
https://github.com/w3c/aria/commit/f2caeecce1f879978bc4aa33aa46f61b6ea2c24b

Add new ARIA role map entries for "insertion" and "deletion" which map to the CONTENT_INSERTION and CONTENT_DELETION Gecko roles, respectively. This is similar to the blockquote ARIA role:
https://searchfox.org/mozilla-central/rev/227f5329f75bd8b16c6b146a7414598a420260cb/accessible/base/RoleMap.h#1598
This might require new entries in nsgkAtoms.
Of course, add tests! accessible/tests/mochitests/role/test_aria.html

https://hg.mozilla.org/mozilla-central/rev/ad9f9646f46c

Since the status are different for nightly and release, what's the status for beta?
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This is a relatively recent addition to the ARIA spec. I don't think we need to uplift this.