Furtwängler made 4 recordings of Bruckner’s Symphony no. 8. The most comprehensive online resources (covering details relevant for MB) I can find is the Tahra related Furtwängler discography (including other labels) and the discography of the Bruckner Society of America. Their combined data:
1944.10.17 | Wien, Musikverein, Großer Saal | Wiener Philharmoniker | Live (Magnetofonkonzert) | No audience
1949.3.14 | Berlin-Dahlem (Gemeindehaus) | Berliner Philharmoniker | Live (Sender Freies) | No audience
1949.3.15 | Berlin, Titania Palast | Berliner Philharmoniker | Live (RIAS) | Audience
1954.4.10 | Wien, Musikverein, Großer Saal | Wiener Philharmoniker | Live | Audience
Symphony versions used are:
1944, -49: Edition prepared by Furtwängler based on Haas and earlier editions
1954: 1892 Version by Bruckner and Joseph Schalk. Ed. Haslinger-Schlesinger-Lienau
For online sources only:
See release Palladio (Enterprise) PD 4135 of the 1944 recording (editing history). Release states incorrectly recording orchestra, date and place:
Incorrect “Berliner Philharmoniker”, “Berlin, 1949”
is in fact ‘Wiener Philharmoniker; Wien, Musikvereinssaal 1944.10.17 .
This is often the case with historical recordings on most labels (big ones as well), but this one a bit more problematic, as 2 of the foremost authorities counted on to be correct has incorrect/conflicting data too: The Bruckner Society of America (online as abruckner.com) and the French Société Wilhelm Furtwängler (furtwangler.net/org):
The abruckner.com discography entry for the Palladio release (above) is wrong in stating “Incorrectly dated 14/3/49” (correct: “Berlin, 1949”, cf. scan).
The French Société Wilhelm Furtwängler adds to the confusion, stating incorrectly on http://www.furtwangler.net/bestchoice.html that the 1944 recording orchestra was Berliner Philharmoniker (also leaving the reader guessing which of the 2 1949 recordings is held the highest), but in the same Society’s Critical Discography by Philippe Leduc, which is not critical but a tops recommendation list, correctly that it is a “Magnetofonkonzert of the VPO [Vienna Philharmonic Orchestra]. (PDF available @ https://www.abruckner.com/articles/articlesenglish/furtwanglersociety/)
I will email both societies a note on this, but with reference to the MB release entry, so I did that one first.