The default ISO didn't come with non-free drivers until the latest release (12, bookworm). Unless you used the "unofficial" image which did include them. Now the situation is different.
Here is the relevant part from the release notes:
> In most cases firmware is non-free according to the criteria used by the Debian GNU/Linux project and thus cannot be included in the main distribution. If the device driver itself is included in the distribution and if Debian GNU/Linux legally can distribute the firmware, it will often be available as a separate package from the non-free-firmware section of the archive (prior to Debian GNU/Linux 12.0: from the non-free section).
> However, this does not mean that such hardware cannot be used during installation. Starting with Debian GNU/Linux 12.0, following the 2022 General Resolution about non-free firmware, official installation images can include non-free firmware packages. By default, debian-installer will detect required firmware (based on kernel logs and modalias information), and install the relevant packages if they are found on an installation medium (e.g. on the netinst). The package manager gets automatically configured with the matching components so that those packages get security updates. This usually means that the non-free-firmware component gets enabled, in addition to main.
Here is the relevant part from the release notes:
> In most cases firmware is non-free according to the criteria used by the Debian GNU/Linux project and thus cannot be included in the main distribution. If the device driver itself is included in the distribution and if Debian GNU/Linux legally can distribute the firmware, it will often be available as a separate package from the non-free-firmware section of the archive (prior to Debian GNU/Linux 12.0: from the non-free section).
> However, this does not mean that such hardware cannot be used during installation. Starting with Debian GNU/Linux 12.0, following the 2022 General Resolution about non-free firmware, official installation images can include non-free firmware packages. By default, debian-installer will detect required firmware (based on kernel logs and modalias information), and install the relevant packages if they are found on an installation medium (e.g. on the netinst). The package manager gets automatically configured with the matching components so that those packages get security updates. This usually means that the non-free-firmware component gets enabled, in addition to main.
https://www.debian.org/releases/bookworm/amd64/ch02s02.en.ht...