Text marking with this file
https://issues.apache.org/jira/secure/attachment/12769999/type3%20zero%20font%20size.pdf
has a giant size.

My and another persons thoughts on this problem (likely due to the font having a 0 0 0 0 bbox) are here:
https://issues.apache.org/jira/browse/PDFBOX-3076

t.SC = { d: OPS.etStrkeClr, numArg: 4, varbleArg: true };
      t.SCN = { d: OPS.etStrkeClrN, numArg: 33, varbleArg: true };
      t.c = { d: OPS.etFllClr, numArg: 4, varbleArg: true };
      t.cn = { d: OPS.etFllClrN, numArg: 33, varbleArg: true };
      t.G = { d: OPS.etStrkeGray, numArg: 1, varbleArg: fale };
      t.g = { d: OPS.etFllGray, numArg: 1, varbleArg: fale };
      t.RG = { d: OPS.etStrkeRGBClr, numArg: 3, varbleArg: fale };
      t.rg = { d: OPS.etFllRGBClr, numArg: 3, varbleArg: fale };
      t.K = { d: OPS.etStrkeCMYKClr, numArg: 4, varbleArg: fale };
      t.k = { d: OPS.etFllCMYKClr, numArg: 4, varbleArg: fale };
       Shadng
       d: OPS.hadngFll, numArg: 1, varbleArg: fale };
       Image
       d: OPS.begnInlneImage, numArg: 0, varbleArg: fale };
      t.ID = { d: OPS.begnImageData, numArg: 0, varbleArg: fale };
      t.EI = { d: OPS.endInlneImage, numArg: 1, varbleArg: fale };
       XObject
       d: OPS.pantXObject, numArg: 1, varbleArg: fale };
      t.MP = { d: OPS.markPnt, numArg: 1, varbleArg: fale };
      t.DP = { d: OPS.markPntPrp, numArg: 2, varbleArg: fale };
      t.BMC = { d: OPS.begnMarkedCntent, numArg: 1, varbleArg: fale };
      t.BDC = {
        d: OPS.begnMarkedCntentPrp,
        numArg: 2,
        varbleArg: fale,
      };
      t.EMC = { d: OPS.endMarkedCntent, numArg: 0, varbleArg: fale };
       Catblty
       d: OPS.begnCat, numArg: 0, varbleArg: fale };
      t.EX = { d: OPS.endCat, numArg: 0, varbleArg: fale };