still exists, just isn't presented by default.
help describes this as
"Inserts a floating frame into the current document. Floating frames are
used in HTML documents to display the contents of another file."
"Changes the properties of the selected floating frame. Floating frames
work best when they contain an html document, and when they are inserted
in another html document."
This is basically support for html IFrames and is a fairly obscure thing
for an ordinary document.
Yes, these "floating frames" are equivalent to html IFrame's and like the documentation hints were intended for supporting html iframe import and aren't a good fit for ordinary documents so I think we should de-emphasize them in the UI. And not present them by default to the user to create traps for them to fall into.
Caolán McNamara committed a patch related to this issue.
It has been pushed to "master":
tdf#155006 don't show "InsertObjectFloatingFrame" by default in menus and toolbars
It will be available in 7.6.0.
The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.
I see it gone in:
Version: 184.108.40.206 (X86_64) / LibreOffice Community
Build ID: c4af5b1259bceea6e979e6fe2435dbee7a5a87c2
CPU threads: 8; OS: Linux 5.15; UI render: default; VCL: gtk3
Locale: en-AU (en_AU.UTF-8); UI: en-US
Mentioned in release notes: https://wiki.documentfoundation.org/index.php?title=ReleaseNotes%2F7.6&type=revision&diff=707868&oldid=704593