[justlurking]

It looks like they built her a box to stand on, so they are making her podium bigger to compensate for her new height.

No, look closely at the yellow box.

It says "Lecturn Power Supply + ?MX"

I can't quite decipher the last three letters, but it looks like it ends in "MX".

[GregoTX]

You might be right. I was basing my post on the article that said:
"The WABC journalist gained exclusive access to the podiums, which not only show Clinton’s is now a bit larger than Trump’s, but that there is also a small box Clinton might stand on."

[hoosiermama]

Bmx I asked up thread. It’s microphone materials