For further investigation: [...] How much more than 'Zonal 1.2b, Struga 1995' is available on Olimpbase?
Unable to find an index to zonals on the site, I concentrated on the directory where the zonal files are located: olimpbase.org/ind-wcc. I loaded the filenames of the zonal pages into a database and learned that they were all similarly structured:-
[cycle]-zonal[info], e.g. 'wc1998-zonal12b' for the Struga 1995 page mentioned above.
This let me count the number of zonals available for each [cycle], as shown in the following chart (excludes playoffs).
For example, the 'wc1998' cycle has 21 zonals associated with it, of which one is the Struga 1995 page. The codes shown in red in the last column correspond to my system of numbering the cycles. From this we can see that cycles C01 through C10 are represented, C11 to C14 are missing, and C15 to C20 are represented, although C20 has only a single zonal. (The current cycle is C29.)
The largest number of zonals are from the 'wc1996' cycle (C16), so I decided to compare the Olimpbase data with my own data on the page C16: 1993-1996 Zonal Cycle. The word 'compare' isn't the most precise term, because Olimpbase has full crosstables, round-by-round progress, and much more, where I often have only the year/place of the event with a clipping to confirm its existence elsewhere in chess literature. For example, my C16 page mentions,
1.5a Kladovo YUG 1993-06
1.5a Zouberi 1993-00
On several occasions I've looked for more info about these events, without success. The equivalent Olimpbase page, Zonal 1.5a, Kladovo/Zouberi 1993, has crosstables for both events plus links to a corresponding PGN file and a playoff. The Olimpbase home page, OlimpBase :: the encyclopaedia of team chess (olimpbase.org), currently says, 'Individual tournament finally available - a long expected feature is ON', plus:-
Under construction a.o.: Individual World Championship (including complete results of zonals) Individual Continental Championship (Panamerican, Asian, African, European) - most complete! [...]
This indicates that the championships of the four continents, which are equivalent to zonals for cycle qualification, are available elsewhere. The site's right sidebar lists all four under 'Continental Championships', but the links only lead back to the Olimpbase home page. Technical glitches of this sort are common on new resources. The timestamps on the zonal pages show that most were released on May 2020, so I expect we'll see updates at some time in the future.
OlimpBase's Wojciech Bartelski shows once again that he is a trailblazer in chess history. Thanks, Wojciech!
The site's right sidebar lists all four under 'Continental Championships', but the links only lead back to the Olimpbase home page. Technical glitches of this sort are common on new resources.
...the 'glitch' was mine. I was trying to open the links in a new browser tab -- as I often do -- but the target page was not loading as it usually does. It was defaulting to the site's home page. A straightforward click on the link produces the desired target page. Apologies for the misleading remark!