I would tack on -v1.0 to the info URIs for consistency, and I'll avoid
pointing out the need for ident: prefix on the sub-elements as I'm sure
you left it out intentionally for readability.

>        <extraRequestData>
>          <ident:clientInfo xmlns:ident="info:srw/extension/1/ident">
>            <institution>Texas State Libraries and Archives</institution>
>            <vendor>Index Data ApS.</vendor>
>            <application>YAZ command-line client</application>
>            <version>2.0.35</version>
>          </ident:clientInfo>
>        </extraRequestData>

Which is great for SRW, but 4 params for SRU...

...&x-info1-clientInstitution=Texas%20...&x-info1-clientVendor=Index...
    &x-info1-clientApplication=...&x-info1-clientVersion=2.0.35

>        <extraResponseData>
>          <ident:serverInfo xmlns:ident="info:srw/extension/1/ident">
>            <institution>Library of Congress</institution>
>            <vendor>Endeavor Information Systems Incorportated</vendor>
>            <application>Voyager</application>
>            <version>0.01</version>
>          </ident:serverInfo>
>        </extraResponseData>

We need a request for this as well, beyond the clientInfo.

How about 'x-info1-serverInfo'  for SRU and
<ident:serverInfo xmlns:ident="info:srw/extension/1/ident-v1.0"/> for SRW?

Rob

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