Hildegard Trabant was murdered by the East German border police (namely, Kurt Renner) on August 18, 1964, and buried on September 23, 1964, at the Frieden-Himmelfahrt (now the Evangelischer Friedhof Nordend) cemetery, north of Pankow, in Niederschönhausen. If you wish to visit Hildegard Trabant’s grave, you must first decide if you’re coming by automobile or by public transportation. If you’re coming by automobile, program your Garmin (if you have one) to 13158 Berlin, Dietzgenstraße 120. This will take you to the cemetery south entrance (Eingang A).

Bus 107
If you're using public transportation, you'll need to decide which is better for you, between the U2, S2, S8, or S9 to U/S-Bhf Pankow, or, the S1 to  U/S-Bhf Wittenau.

Bus 124
If you choose Pankow, find your way to Bus #107, going towards Schildow (Kirche). The bus stop "Zionsfriedhof" will be the 10th stop, about 13 minutes driving time.

If you choose Wittenau, find your way to eBus #124. The bus stop "Zionsfriedhof" will be the 16th stop, about 20 minutes driving time.

Once getting off of the bus at the Zionsfriedhof stop, you can enter the cemetery from the south of the Bushaltestelle at Dietzgenstraße 120 (Eingang A, below). Entering the cemetery at Dietzgenstraße 130 (Eingang B) is theoretically possible, and a more direct shot to the cemetery chapel (Feierhalle), but this entrance was closed when I was there.
Eingang A (closeups below)

Once inside, make your way north to the path leading to the Feierhalle. Once you reach the Feierhalle, turn left; this path will take you to the Urnehnain Himmerfahrt (UH on the map). Hildegard Trabant’s grave will eventually be on the right, today marked at UH Him – B102.

Feierhalle (von Eingang B)
Feierhalle (von hier links gehen)

While the grave is no longer marked with her name, her urn is still there. This is because Frau Trabant was buried in a "linear grave" - a grave which expired after the lawful regulated 20 years of resting allowed under GDR law without becoming a family grave, meaning the family continues to maintain, or another family member is buried more recently there. This period of resting "expired" in 1984, and since then, this particular section of the cemetery was rearranged Previously, her grave number was UH Him - 234a. The "new" grave number is UH Him - B102. This has been described to me as "Urnenhain Himmelfahrt", a beautiful urn grove, which Frau Trabant certainly deserved.
Hildegards Grab (closeups below)

grave from the reverse side
During the GDR era, unlike with Ida Siekmann, it was not possible to remember Frau Trabant as a Maueropfer, because in the GDR, there were no victims of the Berlin Wall. This adds to why she is seemingly so conveniently forgotten in history; the GDR regime and its security forces wanted to literally bury her and all evidence of her, then wash their hands of her. Which contrasts with Frau Siekmann's situation, which occurred on the FRG side of the Berlin Wall; her grave was always maintained, even after the "resting period" (which was 25 years in the FRG), because her grave was considered to be of historical value
Cemetery Register
Cemetery Register, Page 48