From the blue I got a message including this ...

Below is the excerpt from the Oracle UPK installation manual.

Configure Developer Installation with Firebird Components
You can configure the contents of the Developer installation
CD to automatically include the appropriate Firebird component
files. This will make installing the Developer easier since
it will bypass the Firebird prompts in the Setup program for
other authors that need to install the Developer. You should
copy the contents of the product CD to a network drive that
is accessible to any authors that need to install the Developer.

You should also download and extract or install the files mentioned
in the Single-User and Client installation procedures described
later in this section of the manual.

You should copy all of the files that you extracted from the
Firebird-2.0.0.12748-0_embed_win32.zip .zip file and paste them
into the setup\third party files\other folder where you copied
the contents of the Developer CD.

Next, you should navigate to where the Firebird Client is
installed (default installation folder is
C:\Program Files\FirebirdClient)
and copy FirebirdSql.Data.FirebirdClient.dll and paste it into
the setup\third party files\other folder (where you copied
the contents of the Developer CD).

When authors run the Developer setup from your shared drive, they are
not prompted to download the Firebird components.