GDAL - Geospatial Data Abstraction Library
It is sometimes pronounced "goo-doll" (a bit like goo-gle), while others pronounce it "gee-doll," and others pronounce it "gee-dall."
Listen how Frank Warmerdam pronounces it and the history behind the acronym.
OGR used to be a separate vector IO library inspired by OpenGIS Simple Features which was separated from GDAL. With the GDAL 2.0 release, the GDAL and OGR components were integrated together.
See OGR.
See CPL.
See VSI.
In late 1998, Frank Warmerdam started to work as independent professional on the GDAL/OGR library.
No, GDAL/OGR is a Free and Open Source Software.
See License
You can use GDAL/OGR on all modern flavors of Unix: Linux, FreeBSD, Mac OS X; all supported versions of Microsoft Windows; mobile environments (Android and iOS). Both 32-bit and 64-bit architectures are supported.
Plenty! Among the available options, QGIS is an excellent free and open source application with a rich graphical user interface. It allows users to display most GDAL raster and vector supported formats and provides access to most GDAL utilities through its Processing toolbox.
You can also consult the list of software using GDAL.
GDAL/OGR must be compiled with a C++17 capable compiler since GDAL 3.9 (C++11 in previous versions)
Build requirements are described in Build requirements.
See Community
Keep in mind, the quality of the answer you get does bear some relation to the quality of the question. If you need more detailed explanation of this, you can find it in essay How To Ask Questions The Smart Way by Eric S. Raymond.
To some extent this is now covered by the Raster driver implementation tutorial and Vector driver implementation tutorial
While some vector drivers in GDAL support 3D geometries (e.g. reading CityGML or AIXM through the GML driver, or 3D geometries in GeoPackage), 3-dimensional scenes or models formats (such as glTF, OBJ, 3DS, etc.) are out-of-scope for GDAL. Users may consider a library such as ASSIMP (Open-Asset-Importer-Library) for such formats.
See Multi-threading
No, GDAL itself is an open-source software and project, not a Vendor. If your organization considers they need a VPAT or Section 508 form to be able to use GDAL, it is their responsibility to complete the needed steps themselves.
See CITATION