The 3GPP (3rd Generation Partnership Project, created late 90's) is aimed towards the development of standards for the various generations of mobile networks, from 3G to 5G, and its specifications use a large part of the IETF standards.
The 3GPP is organized in 3 main domains or TSGs (Technical Specification Groups): Radio Access Networks (RAN), Service and Systems Aspects (SA), Core Networks and Terminals (CT). New Specifications, or new versions of a number of Specifications, are produced just after the quarterly plenary meetings for each domain. The 3GPP creates Word documents and afterwards, each Organizational Partner (there are 7 ones from Europe, North America and Asia) can produce a PDF version, especially the ETSI version.
As a result, we are necessarily outside, and in front of the 3GPP Standardization space made up of individual documents, organized in series.
Ideally, there should be a single HTML standardization space, with accurate references to sections within specifications, instead of references to documents.
The best we can do is to create a homogeneous space in front of the 3GPP site, made up of descriptors for each technical specification or report. In the end, you will have to get and read each 3GPP document you are interested in.
The way the 3GPP produces TS (Technical Specifications) and TR (Technical Reports) impacts the creation of this frontal space. 3GPP plenary meetings (one for each TSG) are organized at the end of each quarter. Afterwards, a number of 3GPP documents are released in Word format during the first month of the following quarter (as a ZIP file possibly with additional annexes for data). Then, the ETSI publishes a PDF version, much more useful for a reader. However, the PDF is a closed environment by itself, isolated from the other 3GPP documents. Due to the workload for the ETSI, when the whole set of PDFs is published the next plenary meetings are upcoming, or have already started, bringing new versions.
For a better overview of the contents of a specification or report, we reproduce the Table of Contents (ToC). A particularity of 3GPP standards development is that the original section numbers in a document are preserved. It can be extended, but a deleted section will appear as 'Void' and a section inserted between sections with consecutive numbers will be suffixed with a letter. We have taken advantage of this in order to highlight the number of the 3GPP Release number at which a section, and by the way a topic, has been taken into account during the evolution of a document. Up to now, we had provided through the ToC, a direct access to the PDF on the 3GPP site. This is being deconstructed since it loads the ETSI Hosting server for a limited interest, all in all. Furthermore we need to wait, sometimes several weeks, for the availability of the PDF to update this ToC.