If they choose to they could have (in the ARIN region) signed a LRSA,
but that's even been removed, in favor
of the now much more watered down RSA.

I believe ARCD would have been required to sign an LRSA (if they had not previously) in order to transfer the block to Amazon.  

Also, a question for perhaps John here. 

Organization:   Amazon Technologies Inc. (AT-88-Z)

https://www.arin.net/about/corporate/agreements/rsa_faq/#legacy-resource-holder-faq

How do I know if my legacy number resources are already covered under an LRSA or not?
Typically, any legacy number resources that are covered under an LRSA will be associated with an Organization ID ending in a “-Z”. If you have any questions regarding your legacy resources, please contact ARIN’s Registration Services Department. You may contact the Registration Services Help Desk at +1.703.227.0660 or by submitting an Ask ARIN ticket via your ARIN Online account. 

Unless there was a clerical error somewhere, is this telling us that 44.192.0.0/10 remains classified as a legacy resource? I didn't think that was possible given that Amazon was not the original assignee. 

On Fri, Jul 19, 2019 at 11:19 AM Christopher Morrow <morrowc.lists@gmail.com> wrote:
On Fri, Jul 19, 2019 at 10:58 AM Matt Harris <matt@netfire.net> wrote:

>Hence it's no longer "legacy" space that isn't covered by an RIR RSA but is instead now covered by an ARIN RSA.
>

'RIR RSA" is not a thing.
Legacy blocks are basically drifting in the winds... there's no
requirement on the holders to do anything really..
If they choose to they could have (in the ARIN region) signed a LRSA,
but that's even been removed, in favor
of the now much more watered down RSA.